Make use of v8 cached data

Disable Find and Selection highlight
Refactoring - Rename to Default preferences

Smarter search batching

* Use Strict Null Checks In TS Extension

Updates the Ts extension to use strict null checks.

* Throw instead of returning undefined in some linkedmap cases

* fix small null check in buffersync

* Fix for request item null

**Bug**
In the markdown preview, clicking on a page link causes the editor to go blank. This effects our release notes.

**Fix**
Fix the webview pre script which was accidentially slightly changed when it was extracted.

Fixes #4641

Adds basic settings for controlling the markdown preview font. We already support this with custom css, but these settings are similar to what the editor and integrated terminal expose and allow for a few basic customizations. Custom style sheets will override these.

more realistic

fix #16329

Fix #15765. Update textarea state even if there is no selection change in composition