Bug 1579845 - ride along: treeherder: Rename ml to mozlint r=ahal

ML now means Machine Learning for most people, we should be more explicit for new comers

Differential Revision: https://phabricator.services.mozilla.com/D45488

--HG--
extra : moz-landing-system : lando

taskcluster/ci/source-test/python.yml

@@ -152,7 +152,7 @@ mozlint:
         - windows10-64/opt
     python-version: [2]
     treeherder:
-        symbol: ml
+        symbol: mozlint
     run:
         using: python-test
         subsuite: mozlint