Fixes #91238

Fixes #84033

Enables intellisene in the keybindings json editor for code actions and refactorings. Uses the new contribution point from #82718

The major change with the unit tests was no longer requiring
a secondary null field for dispatchparts. As chords can be any length,
it's more forward-thinking to modify the unit tests to accept new behavior.

Also trying to align cases of `getKeyBinding`. Somtimes it returns null and sometimes it returns undefined. Prefer using undefined for all cases

As a start to support key chords of longer than two parts,
modifying the internal structure of ChordKeybinding to not specifically
call out two parts.

* Converted another ~70 test files to strictNullChecks

These are the remaining test files that didn't require any changes to non-test file types. I'll send those in separately.

Most changes were automatic and small (`!`s).
The only non-trival change is that `extHostSearch.ts` needs an interface for its test data.

Again used [TypeStat](https://github.com/JoshuaKGoldberg/TypeStat) when possible per #65581. I'm happy to split this up into smaller PRs if you'd prefer!

* Added missing `!`s to `commands.test.ts`

* Manually added strict null checks in around 70 files

* Fixed tsconfig.strictNullChecks.json merge fail

* Touched up a few unnecessary type changes

* Removed files already in other PRs

* update to 3.0.0-beta.3

* update d.ts files; rename NodeBuffer => Buffer

* update to 3.0.0-beta.4

* undo invalid change

* remove some Electron 2.0.x specific workarounds

* pinch zoom is now disabled by default

* update vscode-nsfw

* change vscode-nsfw

* update smoke test electron version

* streams: use destroy() over close()

* workaround broken tests

* bump distro and OSS

* try to bump node version for build

* update macOS build to use node.js 10.8.0

* fix extension tests

* use node.js 10.2.1 for all builds

* remove nsfw from dev dependencies

* back to node 8.x for build

* Revert "back to node 8.x for build"

This reverts commit 90ea2b7af2a1930e60f86fcef7ef9e2c49a79a8a.

* update distro

* disable test run on macOS prod build for now

* bump distro

* ensure proper nsfw dep

* fix more native dependencies

* temp disable failing test

* fix packages

* update deps

* fix deps

* update deps

* enable macOS unit tests again

* fix deprecated buffer use

* Electron 3.0.0.beta.5

* bump deps

* fix tree accidentally treating auxclick as click

* improve overlay cleanup scheduler (fixes flicker seen with Electron 3.0.x)

* update distro

* remove obsolete disableBlinkFeatures: 'Auxclick'

* update to Electron 3.0 beta 6

* fix compile

* workaround #56994

* do not use backgroundColor to find shared process (causes flicker)

* fix flicker on windows from shared process background color

* webview - bubble up keyboard events (workaround for #56988)

* bump electron to 3.0.0-beta.8

* webview - fix deprecation

* webview - fix another deprecation

* debt - handle SIGPIPE on more processes

* workaround more webview focus issues (for #56988)

* webview - use proper way to focus()

* debt - avoid window-focus/blur and use native focus events instead

* webview - restore previous focus method

* webview - improve focus tracking (do not rely on DOM events)

* bump to electron 3.0.0-beta.9

* update deps

* update electron@3.0.0-beta.10

* webview - do not rely on DOM focus for certain commands (for #56988)

* update to electron@3.0.0-beta.11

* electron@3.0.0-beta.12

* update to beta 13

* update to electron 3.0.0

* update to Electron 3.0.1

* electron@3.0.2

* revert build changes (node.js version)

* try with: enable mojave dark mode support

* fix types

* electron 3.0.3

* electron@3.0.4

* fix deps

* bump electron@3.0.6

* bump electron@3.0.9

* fix strict null issue

* reset format

* bump electron@3.0.10

* fix strict null issue

* webview - print error when revive fails

* electron 3.0.x - try to fix keybindings in webviews (#64417)

* bump @types/node => ^10.12.12

* 💄

* update distro

This code pattern indicates that the type should be nullable

In these cases, the programmer has explicitly indicated that the type should be nullable

We compile using the alwaysStrict flag so these directives are not needed

This part removes most `use strict` directives that are right after the file header

We set alwaysStrict so this directive is not needed

Standardizing syntax and discouraging use of `this` inside tests

Fixes #53002