Add typedoc missing comments

[carolhmj]

This PR adds missing comments detected by our typedoc script. It also marks the method ReviewUniform in the CustomMaterial class as @internal. And it adds an extra check to the typedoc script to detect some comments that weren't picked up.

[bjsplat]

Please make sure to label your PR with "bug", "new feature" or "breaking change" label(s).
To prevent this PR from going to the changelog marked it with the "skip changelog" label.

[bjsplat]

Please make sure to label your PR with "bug", "new feature" or "breaking change" label(s).
To prevent this PR from going to the changelog marked it with the "skip changelog" label.

[bjsplat]

Snapshot stored with reference name:
refs/pull/14717/merge

Test environment:
https://babylonsnapshots.z22.web.core.windows.net/refs/pull/14717/merge/index.html

To test a playground add it to the URL, for example:

https://babylonsnapshots.z22.web.core.windows.net/refs/pull/14717/merge/index.html#WGZLGJ#4600

Links to test babylon tools with this snapshot:

https://playground.babylonjs.com/?snapshot=refs/pull/14717/merge
https://sandbox.babylonjs.com/?snapshot=refs/pull/14717/merge
https://gui.babylonjs.com/?snapshot=refs/pull/14717/merge
https://nme.babylonjs.com/?snapshot=refs/pull/14717/merge

To test the snapshot in the playground with a playground ID add it after the snapshot query string:

https://playground.babylonjs.com/?snapshot=refs/pull/14717/merge#BCU1XR#0