Various commenting improvements (#4941)

* fix: New threads attached to previous as replies

* fix: Cannot use floating toolbar properly in comments

* perf: Avoid re-writing history on click in editor

* fix: Comment on text selection

* fix: 'Copy link' on comments uses wrong hostname

* Show comment buttons on input focus rather than non-empty input
Increase maximum sidebar size

* Allow opening comments from document menu

* fix: Clicking comment menu should not focus thread

* fix: Selection color

* fix: Draft comments not restored

* Add border above document level comment input

* fix: Floating toolbar not constrainted by offset parent

* fix flash of no comment on saving

* fix: Clicking on editor does not remove draft mark

shared/editor/components/Styles.ts

@@ -97,10 +97,6 @@ math-block .katex-display {
   margin: 0;
 }
 
-p::selection, p > *::selection {
-  background-color: #c0c0c0;
-}
-
 .katex-html *::selection {
   background-color: none !important;
 }