runtime(doc): Fix typos in several documents

closes: #15034

Signed-off-by: h-east <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 7ec47bd..c07c3a4 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -1,4 +1,4 @@
-*syntax.txt*	For Vim version 9.1.  Last change: 2024 Jun 13
+*syntax.txt*	For Vim version 9.1.  Last change: 2024 Jun 17
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -5685,9 +5685,9 @@
 							*hl-PmenuThumb*
 PmenuThumb	Popup menu: Thumb of the scrollbar.
 							*hl-PmenuMatch*
-PmenuMatch	Popup menu: Matched text in normal item
+PmenuMatch	Popup menu: Matched text in normal item.
 							*hl-PmenuMatchSel*
-PmenuMatchSel	Popup menu: Matched text in selected item
+PmenuMatchSel	Popup menu: Matched text in selected item.
 							*hl-PopupNotification*
 PopupNotification
 		Popup window created with |popup_notification()|.  If not