colorize: add ability to colorize multiple files into less (#7662)

cless is an alias for a colorized less wrappper: colorize_via_pygmentize_less.
Note that cless opens many files as independent files, navigatable with `:n` and `:p`.

plugins/colorize/colorize.plugin.zsh

@@ -1,5 +1,6 @@
 # easier alias to use the plugin
 alias ccat='colorize_via_pygmentize'
+alias cless='colorize_via_pygmentize_less'  
 
 colorize_via_pygmentize() {
     if ! (( $+commands[pygmentize] )); then
@@ -16,7 +17,7 @@ colorize_via_pygmentize() {
     # guess lexer from file extension, or
     # guess it from file contents if unsuccessful
     local FNAME lexer
-    for FNAME in $@
+    for FNAME in "$@"
     do
         lexer=$(pygmentize -N "$FNAME")
         if [[ $lexer != text ]]; then
@@ -26,3 +27,23 @@ colorize_via_pygmentize() {
         fi
     done
 }
+
+colorize_via_pygmentize_less() (   
+    # this function is a subshell so tmp_files can be shared to cleanup function
+    declare -a tmp_files 
+    
+    cleanup () {
+        [[ ${#tmp_files} -gt 0 ]] && rm -f "${tmp_files[@]}"
+        exit
+    }
+    trap 'cleanup' EXIT HUP TERM INT
+    
+    while (( $# != 0 )); do     #TODO: filter out less opts
+        tmp_file="$(mktemp --tmpdir "tmp.colorize.XXXX.$(sed 's/\//./g' <<< "$1")")"
+        tmp_files+=("$tmp_file")
+        colorize_via_pygmentize "$1" > "$tmp_file"
+        shift 1
+    done
+
+    less -f "${tmp_files[@]}"
+)