runtime(doc): mention mouse scrolling in scrollbind-quickadj (#13190)

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index c512328..f760639 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -6757,9 +6757,9 @@
 			*'scrollbind'* *'scb'* *'noscrollbind'* *'noscb'*
 'scrollbind' 'scb'	boolean  (default off)
 			local to window
-	See also |scroll-binding|.  When this option is set, the current
-	window scrolls as other scrollbind windows (windows that also have
-	this option set) scroll.  This option is useful for viewing the
+	See also |scroll-binding|.  When this option is set, scrolling the
+	current window also scrolls other scrollbind windows (windows that
+	also have this option set).  This option is useful for viewing the
 	differences between two versions of a file, see 'diff'.
 	See |'scrollopt'| for options that determine how this option should be
 	interpreted.