Add time series to glossary

[khallai]

Including the definition for time series in the glossary could be helpful to those new too Prometheus and would like to see a quick reference on the term.

[juliusv]

Hey hey @khallai, thanks! :) I noticed that this and your other recent PRs contain a number of unrelated commits from an earlier pull request (#2376, now merged). Unless changes really are meant to build on top of each other and cannot be sent as separate changes, we'd want each PR to only contain the changes / commits that are meant to be logically part of it - this makes PRs easier to review and also causes fewer merge conflicts and other history confusion issues.

To achieve that, you'd always keep your own local main branch synched to the upstream main branch state and create each new PR branch off of main, rather than branching it off another existing PR branch that already has changes on top of main that are unrelated to the new PR. To fix things retroactively for these PRs, you could probably do something like this:

# Ensure we have all remote objects updated / pulled.
git fetch -a

PR_BRANCH=<your-pr-branch-here> # The branch name of the PR you are fixing

git checkout "$PR_BRANCH"

# Start an interactive rebase of the current branch on top of main
git rebase -i origin/main

# (A text editor will pop up listing all commits in your branch relative to
# where it branched off of main - remove all lines for commits that are
# not related to that PR branch, hit save and exit - the branch should now
# be rewritten to only contain the relevant commits)

# Force push to GitHub to overwrite the remote history
git push -f

Try it on one PR first to see if it works correctly 😅

[khallai]

@juliusv thanks for the guidance I didn't know. I will give it a try and see how it goes. If I get stuck or unsure I'll reach out for some help.