doc: use 'main' branch in UI elements (!12883) · Merge requests · Administrator / sourcegraph · GitLab

Administrator requested to merge docsite/main into main Aug 10, 2020

Created by: bobheadxi

Docsite is now correctly serving stuff on the main branch it seems: https://docs.sourcegraph.com/admin/observability/alert_solutions

however, UI elements still show master - this PR updates it