Rework the utf8proc_decompose_char options description

utf8proc.h

@@ -382,14 +382,14 @@ DLLEXPORT const utf8proc_property_t *utf8proc_get_property(int32_t codepoint);
  * @param dst the destination buffer.
  * @param bufsize the size of the destination buffer.
  * @param options one or more of the following flags:
- * - @ref UTF8PROC_REJECTNA  - an unassigned codepoint leads to an error
- * - @ref UTF8PROC_IGNORE    - "default ignorable" codepoints are stripped
- * - @ref UTF8PROC_CASEFOLD  - unicode casefolding is applied
+ * - @ref UTF8PROC_REJECTNA  - return an error `codepoint` is unassigned
+ * - @ref UTF8PROC_IGNORE    - strip "default ignorable" codepoints
+ * - @ref UTF8PROC_CASEFOLD  - apply Unicode casefolding
  * - @ref UTF8PROC_COMPAT    - replace certain codepoints with their
  *                             compatibility decomposition
- * - @ref UTF8PROC_CHARBOUND - Inserts 0xFF bytes before each grapheme cluster
- * - @ref UTF8PROC_LUMP      - lumps certain different codepoints together
- * - @ref UTF8PROC_STRIPMARK - removes all character marks
+ * - @ref UTF8PROC_CHARBOUND - insert 0xFF bytes before each grapheme cluster
+ * - @ref UTF8PROC_LUMP      - lump certain different codepoints together
+ * - @ref UTF8PROC_STRIPMARK - remove all character marks
  * @param last_boundclass
  * This pointer has to point to an integer variable which is storing
  * the last codepoint's boundary class, if the @ref UTF8PROC_CHARBOUND