Highlight multiline strings as strings instead of comments

Since multiline comments are not officially supported in GDScript, it is
more common to see multiline strings being used as strings rather than
as comments (which are actually standalone expressions here).

This closes #21142.

modules/gdscript/gdscript_editor.cpp

@@ -46,12 +46,12 @@
 void GDScriptLanguage::get_comment_delimiters(List<String> *p_delimiters) const {
 
 	p_delimiters->push_back("#");
-	p_delimiters->push_back("\"\"\" \"\"\"");
 }
 void GDScriptLanguage::get_string_delimiters(List<String> *p_delimiters) const {
 
 	p_delimiters->push_back("\" \"");
 	p_delimiters->push_back("' '");
+	p_delimiters->push_back("\"\"\" \"\"\"");
 }
 Ref<Script> GDScriptLanguage::get_template(const String &p_class_name, const String &p_base_class_name) const {
 #ifdef TOOLS_ENABLED