Add docgen all script and update documentation

[dlarocque]

Since we are now checking in the toc/toc.yaml file, we should have a check to ensure this file was updated, just as we do for docs-devsite.

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[google-oss-bot]

Size Report ¹

Affected Products

No changes between base commit (872e6f6) and merge commit (288c64c).

Test Logs

• Base (872e6f6): https://github.com/firebase/firebase-js-sdk/actions/runs/9322830063
• Merge (288c64c): https://github.com/firebase/firebase-js-sdk/actions/runs/9356846029

1. https://storage.googleapis.com/firebase-sdk-metric-reports/VOZ6Wi2j49.html

[google-oss-bot]

Size Analysis Report ¹

Affected Products

No changes between base commit (872e6f6) and merge commit (288c64c).

Test Logs

• Base (872e6f6): https://github.com/firebase/firebase-js-sdk/actions/runs/9322830063
• Merge (288c64c): https://github.com/firebase/firebase-js-sdk/actions/runs/9356846029

1. https://storage.googleapis.com/firebase-sdk-metric-reports/zPeK7Ec334.html

[hsubox76]

I just realized this outputs to a special toc/ folder which I think is confusing if you're looking at just the Github repo, why it's separated from all the docs. This part we can fix easily (adding the _ to the filename a little more complicated). You can add an --output option here https://github.com/firebase/firebase-js-sdk/blob/master/scripts/docgen/docgen.ts#L153 (see line 270 where we do it for the docgen call). toc is only generated for devsite so you don't have to do the whole ternary we use to get outputFolder in generateDocs, you can just hardcode "docs-devsite".

Come to think of it, you can also mv toc.yaml to _toc.yaml at the end of generateToc and then we don't need to change the google3 side script anymore.

[hsubox76]

LGTM, thanks!

[egilmorez]

LG, thanks!