And don't block-comment inside a block comment

Closes #4208

Closes #4018

Issue #4175

Issue #4162

Closes #4148

When persistent search dialog is open, looking up commands for findNext/
Prev keys would only search the current keyMap. This commit changes this
to also look up commands in extraKeys

Searching with findPersistentNext or findPersistentPrev will
immediately run a search with the previous query, however it will throw
and error if no previous query exists. This commit fixes by preventing
the immediate execution if no previous query is set

Closes #4128

Issue #4112

To match the actual match-highlights in the editor.

Closes #4080

See https://discuss.codemirror.net/t/range-error-with-scrollpastend-addon/773

Issue #4069

Issue #4050

Closes #4056

Issue #4057

Closes #4057

Use findMarks instead of findMarksAt in foldGutter.js to correctly
find marks when a single line is collapsed so that the arrow displays
correctly as collapsed.

Add option 'clearOnEnter' to foldcode.js and default it to true.
This option determines whether the marker added when folding a
line clears when the cursor enters it.

Closes #4042

See https://discuss.codemirror.net/t/width-of-sql-hint-dropdown-in-firefox-is-not-always-correct/757

See https://discuss.codemirror.net/t/dynamically-switch-mode-with-sql-hint-addon-bugs/751

Closes #3896

Closes #4025

Fix "Uncaught TypeError: Cannot read property 'severity' of undefined"

Issue #3974

Even if we don't use promise internally, check for the existence of
`.then` attributes on the return results of a hinting function, and if
so assume it is a promise.

Internally also convert all hinters to use the asynchronous interface
for consistency and simplification of code paths.

Closes #3971

Closes #3972

Issue #3941

Closes #3934