Backport PR #14706 on branch v3.1.1-doc (Mention gr backend in docs.)#14712

timhoffm merged 1 commit into

matplotlib:v3.1.1-docmatplotlib/matplotlib:v3.1.1-docfrom

meeseeksmachine:auto-backport-of-pr-14706-on-v3.1.1-docmeeseeksmachine/matplotlib:auto-backport-of-pr-14706-on-v3.1.1-docCopy head branch name to clipboard