runtime(doc): clarify how fuzzy 'completeopt' should work

related: #14912

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index bc7f687..57fefa2 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -1,4 +1,4 @@
-*options.txt*	For Vim version 9.1.  Last change: 2024 Jun 03
+*options.txt*	For Vim version 9.1.  Last change: 2024 Jun 04
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -2147,7 +2147,10 @@
 	   fuzzy    Enable |fuzzy-matching| for completion candidates. This
 		    allows for more flexible and intuitive matching, where
 		    characters can be skipped and matches can be found even
-		    if the exact sequence is not typed.
+		    if the exact sequence is not typed.  Only makes a
+		    difference how completion candidates are reduced from the
+		    list of alternatives, but not how the candidates are
+		    collected (using different completion types).
 
 					*'completepopup'* *'cpp'*
 'completepopup' 'cpp'	string (default empty)