Triple-colon ligature in ss07 has odd cursor placement in specific scenarios

In `vscode`, the interaction between the triple-colon ligature from ss07 (`:::`) and red squigglies seems to cause issues with cursor placement. Under certain circumstances, the triple-colon ligature renders correctly, but the cursor treats it as two 1.5-wide colon characters and a single 0-width colon.

**I've observed this issue in v1.100 and v1.101, but not in v1.000.**

In this screenshot, the cursor is logically placed between the 1st and 2nd colon from the left, but visually appears in the middle of the 2nd colon:


Moving the cursor right by 1 character places it at the end of the `:::`, and moving it right *again* doesn't visually move the cursor.

After moving it right once:


And again (no visual change):


It's also worth noting that this *only seems to happen* when red squigglies are involved on the right side of the triple-colon ligature:


This is with `ss07` disabled:


This is from v1.000, which doesn't appear to have the ligature:


Also, this seems to only happen with Monaspace's triple-colon ligature. Here's an example of how it looks with Fira Code and its ligatures enabled:


*(I had [originally posted about this](https://github.com/ryanoasis/nerd-fonts/issues/1503#issuecomment-2103966045) in the Nerd Fonts repo related to a different issue I had come across, but this appears to be Monaspace.)*

Inizia riproducendo la triple-colon ss07 ligature in VS Code v1.100 o v1.101 con una sottolineatura ondulata rossa alla sua destra, quindi confronta il comportamento del cursore con ss07 disabilitato, v1.000 e Fira Code. Il lavoro è completato quando il movimento del cursore e il posizionamento visivo rimangono coerenti attraverso la legatura, anche quando sono presenti sottolineature ondulate.

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