patch 8.2.1536: cannot get the class of a character; emoji widths are wrong

Problem:    Cannot get the class of a character; emoji widths are wrong in
            some environments.
Solution:   Add charclass(). Update some emoji widths.  Add script to check
            emoji widths.

runtime/doc/eval.txt

@@ -2425,6 +2425,7 @@ ch_status({handle} [, {options}])
 				String	status of channel {handle}
 changenr()			Number	current change number
 char2nr({expr} [, {utf8}])	Number	ASCII/UTF8 value of first char in {expr}
+charclass({string})		Number	character class of {string}
 chdir({dir})			String	change current working directory
 cindent({lnum})			Number	C indent for line {lnum}
 clearmatches([{win}])		none	clear all matches
@@ -3520,6 +3521,18 @@ char2nr({expr} [, {utf8}])					*char2nr()*
 		Can also be used as a |method|: >
 			GetChar()->char2nr()
 
+
+charclass({string})					*charclass()*
+		Return the character class of the first character in {string}.
+		The character class is one of:
+			0	blank
+			1	punctuation
+			2	word character
+			3	emoji
+			other	specific Unicode class
+		The class is used in patterns and word motions.
+
+
 chdir({dir})						*chdir()*
 		Change the current working directory to {dir}.  The scope of
 		the directory change depends on the directory of the current

runtime/doc/usr_41.txt

@@ -600,6 +600,7 @@ String manipulation:					*string-functions*
 	strtrans()		translate a string to make it printable
 	tolower()		turn a string to lowercase
 	toupper()		turn a string to uppercase
+	charclass()		class of a character
 	match()			position where a pattern matches in a string
 	matchend()		position where a pattern match ends in a string
 	matchstr()		match of a pattern in a string