Add short option -h

It's a classic.
It's a shame it took me almost two decades to add it.

Changelog.txt

@@ -5,6 +5,7 @@ v0.9 beta (unreleased):
   - Fixed to work properly in bash5 (tks Yanmarshus Bachtiar)
   - Fixed eval bug when running in bash3 or newer (tks Marcus Habermehl)
   - New tests for all the command line options (cmdline.md)
+  - Added short option -h (for --help)
   - Converted everything (code and docs) to UTF-8
   - Improved the source code formatting, now it is readable
   - Now using shellcheck to improve code quality

cmdline.md

@@ -13,10 +13,10 @@ $ alias txt2regex="bash ./txt2regex.sh"
 $
 ```
 
-## Option --help
+## Options -h, --help
 
 ```console
-$ txt2regex --help
+$ txt2regex --help | tee help.txt
 usage: txt2regex [ --nocolor | --whitebg ] [ --all | --prog PROGRAMS ]
        txt2regex --showmeta
        txt2regex --showinfo PROGRAM [ --nocolor ]
@@ -36,9 +36,12 @@ OPTIONS (they are default OFF):
   --make LABEL        Prints the default regex for the specified label
 
   --version           Prints the program version and quit
-  --help              Prints the help message and quit
+  -h, --help          Prints the help message and quit
 
 Please read the program Man Page for more information.
+$ txt2regex -h > h.txt
+$ diff help.txt h.txt
+$ rm help.txt h.txt
 $
 ```
 

txt2regex.sh

@@ -130,7 +130,7 @@ Usage(){
     printf '%s\n' $"  --make LABEL        Prints the default regex for the specified label"
     printf '\n'
     printf '%s\n' $"  --version           Prints the program version and quit"
-    printf '%s\n' $"  --help              Prints the help message and quit"
+    printf '%s\n' $"  -h, --help          Prints the help message and quit"
     printf '\n'
     printf '%s\n' $"Please read the program Man Page for more information."
     exit "${1:-0}"  # $1 is the exit code (default is 0)
@@ -268,7 +268,7 @@ do
             printf 'txt2regex v%s\n' "$VERSION"
             exit 0
         ;;
-        --help)
+        -h | --help)
             Usage 0
         ;;
         *)