Merge branch 'retroactive-changelogs' into 'master'

Retroactively add changelogs

See merge request gitlab-org/gitlab-ce!20079

changelogs/unreleased/no-multi-assign-enable.yml

+---
+title: Enable no-multi-assignment in JS files
+merge_request: 19808
+author: gfyoung
+type: other

changelogs/unreleased/no-restricted-globals-enable.yml

+---
+title: Enable no-restricted globals in JS files
+merge_request: 19877
+author: gfyoung
+type: other