Fixes#8616
macOS 26 (as of RC1) has some pathological performance bug where the
terminal becomes unusably slow after some period of time. We aren't 100%
sure what triggers the slowdown, but it is app-wide (new tabs or windows
don't resolve it) and Instruments traces point directly to
NSAutoFillHeuristicController. Specifically, to the `debounceTextUpdate`
selector.
This is all not documented as far as I can find and also not open
source, so I have no idea what's going on.
The best I can tell is that the NSAutoFillHeuristicController has
something to do with enabling heuristic-based autofill such as SMS auth
codes in text input fields. I don't know what is causing it to go
haywire.
SMS autofill is not desirable in a terminal app, nor is any of the other
automatic autofill in macOS I know of (contact info, passwords, etc.).
So, we can just disable it.
This default isn't documented but I found it via a strings dump of the
AppKit binary blob and comparing it to the disassembly to see how it is
used. In my limited testing, this seems to work around the problem.