Fix inaccurate docs in `.aggr()` with `median()` and other non MySQL operations

[ttngu207]

Fix #253

[CBroz1]

@guzman-raphael - Do you know why the publish-release check was skipped? Should we hold off merging pending the full set of tests?

[guzman-raphael]

@CBroz1 It was skipped because we don't publish the docs until the PR is merged. This is evident based on this and this:

on:
  pull_request:
  push:
    tags:
      - '*.*.*'
...
  publish-release:
    if: github.event_name == 'push'
    needs: build
    runs-on: ubuntu-latest

Following merge and a tagging event, it should automatically trigger a redeploy that will publish the new docs.