message: Allow bool

It has always been working even if not documented and there is no reason
to not accept it. However, change "True/False" to "true/false" to be
consistent with meson language.

Fixes: #9436

docs/yaml/functions/message.yaml

@@ -4,11 +4,11 @@ description: This function prints its argument to stdout.
 
 posargs:
   text:
-    type: str
-    description: The message to print
+    type: str | int | bool | list[str | int | bool] | dict[str | int | bool]
+    description: The message to print. Before *0.54.0* only strings was accepted.
 
 varargs:
   name: more_text
   since: 0.54.0
-  type: str
+  type: str | int | bool | list[str | int | bool] | dict[str | int | bool]
   description: Additional text that will be printed separated by spaces.

mesonbuild/interpreter/interpreter.py

@@ -103,12 +103,12 @@ def stringifyUserArguments(args, quote=False):
     elif isinstance(args, dict):
         return '{%s}' % ', '.join(['{} : {}'.format(stringifyUserArguments(k, True), stringifyUserArguments(v, True)) for k, v in args.items()])
     elif isinstance(args, bool):
-        pass # bools are a type of int, make this fallthrough to the error case
+        return 'true' if args else 'false'
     elif isinstance(args, int):
         return str(args)
     elif isinstance(args, str):
         return f"'{args}'" if quote else args
-    raise InvalidArguments('Function accepts only strings, integers, lists, dictionaries and lists thereof.')
+    raise InvalidArguments('Function accepts only strings, integers, bools, lists, dictionaries and lists thereof.')
 
 class Summary:
     def __init__(self, project_name, project_version):