Add search for iframe based webviews. Fixes #96307
Co-authored-by: NMatt Bierner <matb@microsoft.com>

For #120675

This uses a script to add the override keyword to places that need it in the codebase

Note that we can't enable the --noImplicitOverride setting yet since there are still around 200 errors that require further attention

Resolves #107208

Focus notebook find widget when it's shown

Fixes #97204

Fixes #80656

#78168