Variable-sized brackets and bold text break character alignment in Firefox

**Shared Program**: https://code.world/#PL1P3DfDlbKvMjslV59Pugg

**Description**

Consider lines 10 and 11 of the above program:
```haskell
change(w, KeyRelease("Left")) = w { leftReleases = leftReleases(w) + 1 }
change(w, _) = w
```
In Chrome, they look fine:

But in Firefox, the alignment is wrong:

Note the `= w` on line 11 is too far to the left. The same number of characters are there when you count, and it copies and pastes right, so it's just a display bug.

Open the shared CodeWorld program and compare its rendering in Firefox and Chrome, focusing on lines 10 and 11 and the `= w` alignment. Trace the editor or display entry point responsible for character positioning; done means variable-sized brackets and bold text align consistently in Firefox without changing copy-and-paste behavior.

Scritto dal modello di indicizzazione a partire dal testo della issue.