Remove references to gaussholder

[mikelittle]

No description provided.

[hm-backport]

The backport to v14-branch failed:

Commits ["230954186bc65bab70b78a402b87c0227ed706f5","d4bf0adc9598d1ea4e77b2d5a34e982257bc09ac"] could not be cherry-picked on top of v14-branch

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub.
git fetch
# Create new working tree.
git worktree add .worktrees/backport v14-branch
# Navigate to the new directory.
cd .worktrees/backport
# Cherry-pick all the commits of this pull request and resolve the likely conflicts.
git cherry-pick 230954186bc65bab70b78a402b87c0227ed706f5 d4bf0adc9598d1ea4e77b2d5a34e982257bc09ac
# Create a new branch with these backported commits.
git checkout -b backport-290-to-v14-branch
# Push it to GitHub.
git push --set-upstream origin backport-290-to-v14-branch
# Go back to the original working tree.
cd ../..
# Delete the working tree.
git worktree remove .worktrees/backport

Then, create a pull request where the base branch is v14-branch and the compare/head branch is backport-290-to-v14-branch.