More improvements for 'read-buffer's doc string

* src/minibuf.c (Fread_buffer): Further improve the doc
string.  (Bug#347694)

src/minibuf.c

@@ -1111,20 +1111,20 @@ A user option, or customizable variable, is one for which
 
 DEFUN ("read-buffer", Fread_buffer, Sread_buffer, 1, 4, 0,
        doc: /* Read the name of a buffer and return it as a string.
-Prompt with PROMPT.
+Prompt with PROMPT, which should be a string ending with a colon and a space.
+Provides completion on buffer names the user types.
 Optional second arg DEF is value to return if user enters an empty line,
  instead of that empty string.
  If DEF is a list of default values, return its first element.
-Optional third arg REQUIRE-MATCH determines whether non-existing
+Optional third arg REQUIRE-MATCH has the same meaning as the
- buffer names are allowed.  It has the same meaning as the
  REQUIRE-MATCH argument of `completing-read'.
-The argument PROMPT should be a string ending with a colon and a space.
+Optional arg PREDICATE, if non-nil, is a function limiting the buffers that
+can be considered.  It will be called with each potential candidate, and
+should return non-nil to accept the candidate for completion, nil otherwise.
 If `read-buffer-completion-ignore-case' is non-nil, completion ignores
 case while reading the buffer name.
 If `read-buffer-function' is non-nil, this works by calling it as a
-function, instead of the usual behavior.
+function, instead of the usual behavior.  */)
-Optional arg PREDICATE if non-nil is a function limiting the buffers that can
-be considered.  */)
   (Lisp_Object prompt, Lisp_Object def, Lisp_Object require_match,
    Lisp_Object predicate)
 {