Removing `0.8em` VE special base `font-size` for UI as we're unifying
OOUI interfaces to `14px` equals to `0.875em` at user agent default size.
Bug: T97631
Depends-on: I693d168d2ccf2babbcfe8952af3e1c262aa97773
Change-Id: I84edeec38ecfb90f5d53199f3b26fc3f83ab0611
Only shown if VisualEditorEnableDiffPage is set, or query
string param 'visualdiff' is present.
Currently:
* All VE javascript is loaded (could be cut down to just DM code)
* The entire Parsoid HTML of both revisions being compared is loaded
* Both Parsoid HTML docs are parsed into VE DM trees and diffed
Bug: T167508
Change-Id: I151fc9bab3d3032f50c8d11be6b54e45a06fcc34
