I think this would work better as `-tag` list instead of a table. Something like this:

```mdoc
.Bl -tag
.It Ic GCC_WARN_INITIALIZER_NOT_FULLY_BRACKETED
Warn if an aggregate or union initializer …
.It Ic GCC_WARN_MISSING_PARENTHESES
Warn if parentheses are omitted in …
…
.El
```

This will render something like this, giving more space to the descriptions:

```
GCC_WARN_INITIALIZER_NOT_FULLY_BRACKETED
        Warn if an aggregate or union initializer …
GCC_WARN_MISSING_PARENTHESES
        Warn if parentheses are omitted in …
```