Full Unicode support incomplete

### Describe the bug

This is an issue that has been brought up several times through the years but it still not fixed (see for example #1531).

The editor does not handle certain Unicode characters correctly, for example the `Combining Diacritical Marks`. It seems the editor treats these characters as full width characters and the text cursor moves further away from the text.

I described the problem in details here, including pictures: https://github.com/rstudio/rstudio/issues/12680#issue-1575708046 RStudio uses the Ace editor.

### Expected Behavior

Correct handling of Unicode characters.

### Current Behavior

See description.

### Reproduction Steps

See description.

### Possible Solution

_No response_

### Additional Information/Context

_No response_

### Ace Version / Browser / OS / Keyboard layout

Ace Kitchen Sink, Safari, macOS; also embedded editor in RStudio latest