diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index d062af4..c730527 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -1,4 +1,4 @@
-*options.txt*	For Vim version 9.0.  Last change: 2022 Nov 12
+*options.txt*	For Vim version 9.0.  Last change: 2022 Nov 23
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -4548,17 +4548,21 @@
 			|+find_in_path| or |+eval| features}
 	Expression to be used to transform the string found with the 'include'
 	option to a file name.  Mostly useful to change "." to "/" for Java: >
-		:set includeexpr=substitute(v:fname,'\\.','/','g')
+		:setlocal includeexpr=substitute(v:fname,'\\.','/','g')
 <	The "v:fname" variable will be set to the file name that was detected.
-
+	Note the double backslash: the `:set` command first halves them, then
+	one remains it the value, where "\." matches a dot literally.  For
+	simple character replacements `tr()` avoids the need for escaping: >
+		:setlocal includeexpr=tr(v:fname,'.','/')
+<
 	Also used for the |gf| command if an unmodified file name can't be
 	found.  Allows doing "gf" on the name after an 'include' statement.
 	Also used for |<cfile>|.
 
 	If the expression starts with s: or |<SID>|, then it is replaced with
 	the script ID (|local-function|). Example: >
-		set includeexpr=s:MyIncludeExpr()
-		set includeexpr=<SID>SomeIncludeExpr()
+		setlocal includeexpr=s:MyIncludeExpr()
+		setlocal includeexpr=<SID>SomeIncludeExpr()
 <	Otherwise, the expression is evaluated in the context of the script
 	where the option was set, thus script-local items are available.