diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 04cadad..1d70137 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -1,4 +1,4 @@
-*builtin.txt*	For Vim version 9.0.  Last change: 2022 Nov 14
+*builtin.txt*	For Vim version 9.0.  Last change: 2022 Nov 21
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -5572,6 +5572,10 @@
 		If {expr2} is a |Funcref| it is called with two arguments:
 			1. The key or the index of the current item.
 			2. the value of the current item.
+		With a legacy script lambda you don't get an error if it only
+		accepts one argument, but with a Vim9 lambda you get "E1106:
+		One argument too many", the number of arguments must match.
+
 		The function must return the new value of the item. Example
 		that changes each value by "key-value": >
 			func KeyValue(key, val)
@@ -7938,29 +7942,38 @@
 
 setcellwidths({list})					*setcellwidths()*
 		Specify overrides for cell widths of character ranges.  This
-		tells Vim how wide characters are, counted in screen cells.
-		This overrides 'ambiwidth'.  Example: >
-		   setcellwidths([[0xad, 0xad, 1],
-				\ [0x2194, 0x2199, 2]])
+		tells Vim how wide characters are when displayed in the
+		terminal, counted in screen cells.  The values override
+		'ambiwidth'.  Example: >
+		   call setcellwidths([
+		   		\ [0x111, 0x111, 1],
+				\ [0x2194, 0x2199, 2],
+				\ ])
 
-<				*E1109* *E1110* *E1111* *E1112* *E1113* *E1114*
-		The {list} argument is a list of lists with each three
-		numbers. These three numbers are [low, high, width].  "low"
-		and "high" can be the same, in which case this refers to one
-		character. Otherwise it is the range of characters from "low"
-		to "high" (inclusive).  "width" is either 1 or 2, indicating
-		the character width in screen cells.
-		An error is given if the argument is invalid, also when a
-		range overlaps with another.
+<		The {list} argument is a List of Lists with each three
+		numbers: [{low}, {high}, {width}].	*E1109* *E1110*
+		{low} and {high} can be the same, in which case this refers to
+		one character.  Otherwise it is the range of characters from
+		{low} to {high} (inclusive).		*E1111* *E1114*
 		Only characters with value 0x100 and higher can be used.
 
+		{width} must be either 1 or 2, indicating the character width
+		in screen cells.			*E1112*
+		An error is given if the argument is invalid, also when a
+		range overlaps with another. 		*E1113*
+
 		If the new value causes 'fillchars' or 'listchars' to become
 		invalid it is rejected and an error is given.
 
-		To clear the overrides pass an empty list: >
+		To clear the overrides pass an empty {list}: >
 		   setcellwidths([]);
+
 <		You can use the script $VIMRUNTIME/tools/emoji_list.vim to see
-		the effect for known emoji characters.
+		the effect for known emoji characters.  Move the cursor
+		through the text to check if the cell widths of your terminal
+		match with what Vim knows about each emoji.  If it doesn't
+		look right you need to adjust the {list} argument.
+
 
 setcharpos({expr}, {list})				*setcharpos()*
 		Same as |setpos()| but uses the specified column number as the