Add machine translation instructions (#458)

* Add machine translation instructions

Fixes #454.

* Addition instructions for DeepL

Author: rrrutledge

CONTRIBUTING.md

@@ -14,6 +14,8 @@ Here's a few tips as you go along:
 # Translations
 
 * All articles may be translated into any language of interest.
+* Instead of translating from scratch, consider starting with [machine-translated text](https://www.deepl.com/translator) and revising from there.
+Remove "Translated by DeepL" in the final text.
 * Translated articles should be stored next to the English articles in a subfolder named as the [two-character language code](https://www.loc.gov/standards/iso639-2/php/code_list.php) of the translation (e.g. the `de` subfolder for German).
 * The filename of the article should be changed to include two-character language code prefix.
 * The special `index.md` files for each section should also be translated, as they are used in the Learning Path section of the [new website](https://innersourcecommons.net/learn/learning-path/)