runtime(doc): clarify buffer deletion on popup_close()

Reported-by: Lifepillar <[email protected]>
Signed-off-by: Christian Brabandt <[email protected]>

Author: chrisbra

runtime/doc/popup.txt

@@ -1,4 +1,4 @@
-*popup.txt*  For Vim version 9.1.  Last change: 2024 Dec 19
+*popup.txt*  For Vim version 9.1.  Last change: 2025 Jan 08
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -257,8 +257,8 @@ popup_clear([{force}])
 
 
 popup_close({id} [, {result}])				*popup_close()*
-		Close popup {id}.  The window and the associated buffer will
-		be deleted.
+		Close popup {id}.  The window will be deleted.  The associated
+		buffer will be deleted, if the popup created a new buffer.
 
 		If the popup has a callback it will be called just before the
 		popup window is deleted.  If the optional {result} is present