docs(*): update readme and contributing with translation details

Author: perryrh0dan

contributing.md

@@ -36,7 +36,7 @@ You may find an issue is assigned, or has the [`assigned` label](https://github.
 #### Create a Translation
 
 - Check the [`i18n`](https://github.com/perryrh0dan/taskline/tree/master/i18n) directory to ensure that taskline is not already translated in your target language.
-- Add the name of the language as the filename, e.g: `de.json`
+- Add the name of the language as the filename, e.g: `de.json` according to [ISO 3166-1 alpha-2](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2).
 - Place the translated json file inside the ['i18n'](https://github.com/perryrh0dan/taskline/tree/master/i18n) directory.
 - Create a Pull Request including the language in the title, e.g: `Taskline: Russian Translation`
 

readme.md

@@ -563,7 +563,9 @@ Since Taskline 1.1.0 custom themes can be created. The colors of the individual
 
 ## Languages
 
-Actual taskline supports english as default output language and german. Hopefully with you help we are able to translate taskline in much more languages. Visit the [contributing guidelines](https://github.com/perryrh0dan/taskline/blob/master/contributing.md#translating-taskline) to learn more on how to translate taskline into more languages.
+Change the language in the configuration file under language. Actual only english(en) and german(de) is supported.
+
+Actual taskline supports english as default output language and german. Hopefully with your help we are able to translate taskline in much more languages. Visit the [contributing guidelines](https://github.com/perryrh0dan/taskline/blob/master/contributing.md#translating-taskline) to learn more on how to translate taskline into more languages.
 
 ## Development
 
@@ -584,4 +586,3 @@ Currently there are three automated test. ESLint, JSHint and unit tests written
 ## License
 
 [MIT](https://github.com/perryrh0dan/taskline/blob/master/license.md)
-