Tweak CLI ...

* Mention Quit[] will leave CLI
* Allow --colors=None as an alias for --colors=NoColor
  "None" matches the --style option of mathicssscript

Author: rocky

mathics/main.py

@@ -62,6 +62,7 @@ def __init__(self, definitions, colors, want_readline, want_completion):
 
         color_schemes = {
             "NOCOLOR": (["", "", "", ""], ["", "", "", ""]),
+            "NONE": (["", "", "", ""], ["", "", "", ""]),
             "LINUX": (
                 ["\033[32m", "\033[1m", "\033[22m", "\033[39m"],
                 ["\033[31m", "\033[1m", "\033[22m", "\033[39m"],
@@ -248,7 +249,7 @@ def main() -> int:
         "multiple times)",
     )
 
-    argparser.add_argument("--colors", nargs="?", help="interactive shell colors. Use value 'NoColor' to disable ANSI color decoration")
+    argparser.add_argument("--colors", nargs="?", help="interactive shell colors. Use value 'NoColor' or 'None' to disable ANSI color decoration")
 
     argparser.add_argument(
         "--no-completion", help="disable tab completion", action="store_true"
@@ -347,7 +348,7 @@ def main() -> int:
         print()
         print(version_string + "\n")
         print(license_string + "\n")
-        print("Quit by pressing {0}\n".format(quit_command))
+        print(f"Quit by evaluating Quit[] or by pressing {quit_command}.\n")
 
     while True:
         try: