Improve some of the breve/caron/cedilla mappings

* lisp/leim/quail/latin-pre.el ("latin-prefix"): Describe new 'c with
cedilla mapping'.  Extend caron description.  Correct dot above
description.  Add new mappings for 'a with breve' and 'c with caron'.
Add additional mapping for 'c with cedilla'.  Delete ~o mapping for 'g
with dot above'.

lisp/leim/quail/latin-pre.el

@@ -1089,15 +1089,15 @@ of characters from a single Latin-N charset.
 
     effect   | prefix | examples
  ------------+--------+----------
-    acute    |   \\='    | \\='a -> á, \\='\\=' -> ´
+    acute    |   \\='    | \\='a -> á  \\='\\=' -> ´
     grave    |   \\=`    | \\=`a -> à
   circumflex |   ^    | ^a -> â
   diaeresis  |   \"    | \"a -> ä  \"\" -> ¨
     tilde    |   ~    | ~a -> ã
-   cedilla   |   ~    | ~c -> ç
+   cedilla   |  , ~   | ,c -> ç  ~c -> ç
+    caron    |   ~    | ~c -> č  ~g -> ğ
     breve    |   ~    | ~a -> ă
-    caron    |   ~    | ~c -> č
-  dot above  | ~ / .  | ~o -> ġ   /o -> ġ   .o -> ġ
+  dot above  |   / .  | /g -> ġ   .g -> ġ
     misc     | \" ~ /  | \"s -> ß  ~d -> ð  ~t -> þ  /a -> å  /e -> æ  /o -> ø
    symbol    |   ~    | ~> -> »  ~< -> «  ~! -> ¡  ~? -> ¿  ~~ -> ¸
    symbol    |  _ /   | _o -> º  _a -> ª  // -> °  /\\ -> ×  _y -> ¥
@@ -1252,7 +1252,10 @@ of characters from a single Latin-N charset.
  ("~>" ?\»)
  ("~?" ?¿)
  ("~A" ?Ã)
+ ("~A" ?Ă)
  ("~C" ?Ç)
+ ("~C" ?Č)
+ (",C" ?Ç)
  ("~D" ?Ð)
  ("~G" ?Ğ)
  ("~N" ?Ñ)
@@ -1265,13 +1268,15 @@ of characters from a single Latin-N charset.
  ("~Z" ?Ž)
  ("~`" ?˘)
  ("~a" ?ã)
+ ("~a" ?ă)
  ("~c" ?ç)
+ ("~c" ?č)
+ (",c" ?ç)
  ("~d" ?ð)
  ("~e" ?€)
  ("~g" ?ğ)
  ("~n" ?ñ)
  ("~o" ?õ)
- ("~o" ?ġ)
  ("~p" ?¶)
  ("~s" ?§)
  ("~s" ?ş)