runtime(doc): make :h 'completefuzzycollect' a bit clearer

- Fix grammar
- Use "matches" instead of "items" ("completion candidates" is used in
  some other places, but it's a bit verbose)
- "When set" is a bit vague, instead use "For specified modes"

closes: #16871

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: glepnir <glephunter@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/doc/options.txt

@@ -1,4 +1,4 @@
-*options.txt*	For Vim version 9.1.  Last change: 2025 Mar 12
+*options.txt*	For Vim version 9.1.  Last change: 2025 Mar 13
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -2107,11 +2107,11 @@ A jump table for the options with a short description can be found at |Q_op|.
 						*'completefuzzycollect'* *'cfc'*
 'completefuzzycollect' 'cfc'	string	(default: empty)
 				global
-	A comma-separated list of option enables fuzzy collection for specific
+	A comma-separated list of strings to enable fuzzy collection for
-	|ins-completion| modes, affecting how items are gathered during
+	specific |ins-completion| modes, affecting how matches are gathered
-	completion. When set, fuzzy matching is used to find completion
+	during completion.  For specified modes, fuzzy matching is used to
-	candidates instead of the standard prefix-based matching. This option
+	find completion candidates instead of the standard prefix-based
-	can contain the following values are:
+	matching.  This option can contain the following values:
 
 	keyword		keywords in the current file |i_CTRL-X_CTRL-N|
 			keywords with the ".", "w", "b", "u", "U" and