Fix comments in beginning of file

Also improve error for unknown characters.

modules/gdscript/gdscript_tokenizer.cpp

@@ -791,7 +791,7 @@ void GDScriptTokenizer::check_indent() {
 		CharType current_indent_char = _peek();
 		int indent_count = 0;
 
-		if (current_indent_char != ' ' && current_indent_char != '\t' && current_indent_char != '\r' && current_indent_char != '\n') {
+		if (current_indent_char != ' ' && current_indent_char != '\t' && current_indent_char != '\r' && current_indent_char != '\n' && current_indent_char != '#') {
 			// First character of the line is not whitespace, so we clear all indentation levels.
 			// Unless we are in a continuation or in multiline mode (inside expression).
 			if (line_continuation || multiline_mode) {
@@ -1248,7 +1248,7 @@ GDScriptTokenizer::Token GDScriptTokenizer::scan() {
 			}
 
 		default:
-			return make_error("Unknown character.");
+			return make_error(vformat(R"(Unknown character "%s".")", String(&c, 1)));
 	}
 }