Fix styling of Unicode codepoints in manuals

* doc/lispref/nonascii.texi (Character Properties):
* doc/lispref/display.texi (Glyphless Chars)
(Bidirectional Display):
* doc/emacs/search.texi (Lax Search):
* doc/emacs/text.texi (Quotation Marks):
* doc/emacs/basic.texi (Inserting Text): Canonicalize the
style of "U+NNNN CHARACTER NAME".  (Bug#35885)

doc/emacs/basic.texi

@@ -113,7 +113,7 @@ just like digits.  Case is ignored.
 @cindex curved quotes, inserting
   A few common Unicode characters can be inserted via a command
 starting with @kbd{C-x 8}.  For example, @kbd{C-x 8 [} inserts @t{‘}
-which is Unicode code-point @code{U+2018} LEFT SINGLE QUOTATION MARK,
+which is Unicode code-point U+2018 @sc{left single quotation mark},
 sometimes called a left single ``curved quote'' or ``curly quote''.
 Similarly, @kbd{C-x 8 ]}, @kbd{C-x 8 @{} and @kbd{C-x 8 @}} insert the
 curved quotes @t{’}, @t{“} and @t{”}, respectively.  Also, a working

doc/emacs/search.texi

@@ -1310,14 +1310,14 @@ of its accented cousins like @code{@"a} and @code{@'a}, i.e., the
 match disregards the diacritics that distinguish these
 variants.  In addition, @code{a} matches other characters that
 resemble it, or have it as part of their graphical representation,
-such as @sc{u+249c parenthesized latin small letter a} and @sc{u+2100
+such as U+249C @sc{parenthesized latin small letter a} and U+2100
-account of} (which looks like a small @code{a} over @code{c}).
+@sc{account of} (which looks like a small @code{a} over @code{c}).
 Similarly, the @acronym{ASCII} double-quote character @code{"} matches
 all the other variants of double quotes defined by the Unicode
 standard.  Finally, character folding can make a sequence of one or
 more characters match another sequence of a different length: for
-example, the sequence of two characters @code{ff} matches @sc{u+fb00
+example, the sequence of two characters @code{ff} matches U+FB00
-latin small ligature ff}.  Character sequences that are not identical,
+@sc{latin small ligature ff}.  Character sequences that are not identical,
 but match under character folding are known as @dfn{equivalent
 character sequences}.
 
@@ -1642,8 +1642,9 @@ replacement has already been made, @key{DEL} and @key{SPC} are
 equivalent in this situation; both move to the next occurrence.
 
 You can type @kbd{C-r} at this point (see below) to alter the replaced
-text.  You can also type @kbd{C-x u} to undo the replacement; this exits
+text.  You can also undo the replacement with the @code{undo} command
-the @code{query-replace}, so if you want to do further replacement you
+(e.g., type @kbd{C-x u}; @pxref{Undo}); this exits the
+@code{query-replace}, so if you want to do further replacement you
 must use @kbd{C-x @key{ESC} @key{ESC} @key{RET}} to restart
 (@pxref{Repetition}).
 

doc/emacs/text.texi

@@ -428,10 +428,10 @@ using straight apostrophes @t{'like this'} or double-quotes @t{"like
 this"}.  Another common way is the curved quote convention, which uses
 left and right single or double quotation marks `@t{like this}' or
 ``@t{like this}''@footnote{
-The curved single quote characters are U+2018 LEFT SINGLE QUOTATION
+The curved single quote characters are U+2018 @sc{left single quotation
-MARK and U+2018 RIGHT SINGLE QUOTATION MARK; the curved double quotes
+mark} and U+2018 @sc{right single quotation mark}; the curved double quotes
-are U+201C LEFT DOUBLE QUOTATION MARK and U+201D RIGHT DOUBLE
+are U+201C @sc{left double quotation mark} and U+201D @sc{right double
-QUOTATION MARK.  On text terminals which cannot display these
+quotation mark}.  On text terminals which cannot display these
 characters, the Info reader might show them as the typewriter ASCII
 quote characters.
 }.  In text files, typewriter quotes are simple and

doc/lispref/display.texi

@@ -7269,9 +7269,9 @@ Non-@acronym{ASCII}, non-printing characters @code{U+0080} to
 @samp{\230}).
 
 @item format-control
-Characters of Unicode General Category [Cf], such as @samp{U+200E}
+Characters of Unicode General Category [Cf], such as U+200E
-(Left-to-Right Mark), but excluding characters that have graphic
+@sc{left-to-right mark}, but excluding characters that have graphic
-images, such as @samp{U+00AD} (Soft Hyphen).
+images, such as U+00AD @sc{soft hyphen}.
 
 @item no-font
 Characters for which there is no suitable font, or which cannot be
@@ -7654,12 +7654,12 @@ problem:
 
 @itemize @minus
 @item
-Append the special character @code{U+200E}, LEFT-TO-RIGHT MARK, or
+Append the special character U+200E @sc{left-to-right mark}, or
 @acronym{LRM}, to the end of each field that may have bidirectional
 content, or prepend it to the beginning of the following field.  The
 function @code{bidi-string-mark-left-to-right}, described below, comes
 in handy for this purpose.  (In a right-to-left paragraph, use
-@code{U+200F}, RIGHT-TO-LEFT MARK, or @acronym{RLM}, instead.)  This
+U+200F @sc{right-to-left mark}, or @acronym{RLM}, instead.)  This
 is one of the solutions recommended by the UBA.
 
 @item

doc/lispref/nonascii.texi

@@ -550,8 +550,8 @@ characters whose @code{Numeric_Type} is @samp{Numeric}.  The value of
 this property is a number.  Examples of characters that have this
 property include fractions, subscripts, superscripts, Roman numerals,
 currency numerators, and encircled numbers.  For example, the value of
-this property for the character @code{U+2155} (@sc{vulgar fraction one
+this property for the character U+2155 @sc{vulgar fraction one
-fifth}) is @code{0.2}.  For characters that don't have any numeric
+fifth} is @code{0.2}.  For characters that don't have any numeric
 value, and for unassigned codepoints, the value is @code{nil}, which
 means @acronym{NaN}.
 
@@ -622,23 +622,24 @@ is @code{nil}, which means the character itself.
 @item special-uppercase
 Corresponds to Unicode language- and context-independent special upper-casing
 rules.  The value of this property is a string (which may be empty).  For
-example mapping for @code{U+00DF} (@sc{latin small letter sharp s}) is
+example mapping for U+00DF @sc{latin small letter sharp s} is
 @code{"SS"}.  For characters with no special mapping, the value is @code{nil}
 which means @code{uppercase} property needs to be consulted instead.
 
 @item special-lowercase
-Corresponds to Unicode language- and context-independent special lower-casing
+Corresponds to Unicode language- and context-independent special
-rules.  The value of this property is a string (which may be empty).  For
+lower-casing rules.  The value of this property is a string (which may
-example mapping for @code{U+0130} (@sc{latin capital letter i with dot above})
+be empty).  For example mapping for U+0130 @sc{latin capital letter i
-the value is @code{"i\u0307"} (i.e. 2-character string consisting of @sc{latin
+with dot above} the value is @code{"i\u0307"} (i.e. 2-character string
-small letter i} followed by @sc{combining dot above}).  For characters with no
+consisting of @sc{latin small letter i} followed by U+0307
-special mapping, the value is @code{nil} which means @code{lowercase} property
+@sc{combining dot above}).  For characters with no special mapping,
-needs to be consulted instead.
+the value is @code{nil} which means @code{lowercase} property needs to
+be consulted instead.
 
 @item special-titlecase
 Corresponds to Unicode unconditional special title-casing rules.  The value of
 this property is a string (which may be empty).  For example mapping for
-@code{U+FB01} (@sc{latin small ligature fi}) the value is @code{"Fi"}.  For
+U+FB01 @sc{latin small ligature fi} the value is @code{"Fi"}.  For
 characters with no special mapping, the value is @code{nil} which means
 @code{titlecase} property needs to be consulted instead.
 @end table