Backport PR #23868 on branch v3.6.x (Show errors and warnings in doc CI after build.)#24612

tacaswell merged 1 commit intomatplotlib:v3.6.xmatplotlib/matplotlib:v3.6.xfrom

meeseeksmachine:auto-backport-of-pr-23868-on-v3.6.xmeeseeksmachine/matplotlib:auto-backport-of-pr-23868-on-v3.6.xCopy head branch name to clipboard