Closes #4499

Closes #4573

Closes #4568

Closes #4549

Issue #4537

Where it would return a nonsense offset when called for the end of
the document if the last line had line widgets above it.

Issue #4557

To forbid using the comment strings from their inner modes

Closes #4562

Closes #4563

Closes #4472

Issue #4560

Issue #4556

Closes #4554

Closes #4553

Closes #4552

  - Update keywords (remove `ifdef`. add `select`, `uninitialized` and `__END_LINE__`.)
  - Add new string literals (%q string and here docs).
  - Remove global variable syntax (because it is no longer supported.)
  - Improve indentation (fix #3887, and correct indentation of `abstract class`)

Closes #4548

Since it's increased the strangeness of the userAgent string again

Issue #4408

1. End of wrapped line in bidi content is wrong (my mistake)
2. coordsChar({left:0, top: *}) in bidi content is wrong after Marijn's code
   style changes

Closes #4545

The current situation prevents to remove bindings from the default keymap in vim
mode. It is sometimes required to be able to delete them in order to do some
custom mapping.

Example:

1. The `h` binding is defined in the default keymap for moving left.

2. The user want to set the custom binding `h<character>` to behave like
   `r<character>`. It can do so with:

     CodeMirror.Vim.mapCommand('h<character>', 'action', 'replace', {},
                               { isEdit: true, context: 'normal' });

3. When the user press the `h` key, the code searches for all the keybindings
   matching it [1].

4. Two bindings are found:

   - The default binding `h` for moving left. This is a FULL match.
   - The user-defined `h<character>`. This is only a PARTIAL match as it is
     expecting another character.

5. The code is preferring FULL matches over PARTIAL matches whenever they are in
   competition [2]. The code then selects the move left action.

6. The way to let the user-defined binding take over is to let the user delete
   the default binding:

     CodeMirror.Vim.unmap('h');

   but this is not possible because it is not allowed to delete bindings from
   the default keymap [3].

This commit remove such differentiation by treating all bindings in the same
way, letting the responsibility to the user to not mess with the bindings he
needs.

[1] https://github.com/codemirror/CodeMirror/blob/ff84b9ee73b75851801bc4004b75e35fea6291cb/keymap/vim.js#L1098
[2] https://github.com/codemirror/CodeMirror/blob/ff84b9ee73b75851801bc4004b75e35fea6291cb/keymap/vim.js#L1099-L1103
[3] https://github.com/codemirror/CodeMirror/blob/ff84b9ee73b75851801bc4004b75e35fea6291cb/keymap/vim.js#L4182



Signed-off-by: Fabien Dubosson <fabien.dubosson@gmail.com>

Closes #4526