Dehardcode version major in editor settings

Follow-up on 7474fc133a268eae12b7b89307cb0482e3781820.

ISSUE_TEMPLATE.md

@@ -1,6 +1,6 @@
 vvv Remove me vvv
 
-*NOTE:* If you using the current master branch / 3.0-alpha version, do not that
+*NOTE:* If you using the current master branch / 3.0-alpha version, do note that
 breakage is *expected*. Projects from Godot 2.x are expected not to work. Please
 wait for the upcoming stabilisation period to report bugs regarding recent changes.
 

tools/editor/editor_settings.cpp

@@ -328,12 +328,12 @@ void EditorSettings::create() {
 
 		// path at least is validated, so validate config file
 
-
-		config_file_path = config_path+"/"+config_dir+"/editor_settings-3.tres";
+		String config_file_name = "editor_settings-" + String(_MKSTR(VERSION_MAJOR)) + ".tres";
+		config_file_path = config_path + "/" + config_dir + "/" + config_file_name;
 
 		String open_path = config_file_path;
 
-		if (!dir->file_exists("editor_settings-3.tres")) {
+		if (!dir->file_exists(config_file_name)) {
 
 			goto fail;
 		}