Remove legacyCompilerArgsBehavior deprecation.

[sean-mcmanus]

The setting is hard to discover, i.e. hidden, if it's deprecated (no autocomplete or visibility in the settings UI).

[Colengms]

This was intentionally deprecated. We didn't want to advertise this feature. The intention was only to refer people to this setting if they reported an issue it might address. We don't want people using the old behavior unless they absolutely need it.

[bobbrow]

This was intentionally deprecated. We didn't want to advertise this feature. The intention was only to refer people to this setting if they reported an issue it might address. We don't want people using the old behavior unless they absolutely need it.

@Colengms It's impossible to find it in the case that they do need it though. We can deprecate it next release. I'd like to get telemetry on if anyone's using it in the meantime.

[Colengms]

The idea was, if someone reports an issue, we would provide them a line of text to add to settings.json. If they paste the setting in, it squiggles to indicate it's deprecated, but hover still provides documentation and the boolean value still auto-completes. It's working as designed. Ideally, no-one should need to use this setting. We don't want people to discover it. This setting is only for users who report they are dependent on a bug that was fixed and updating their compiler arg values is too inconvenient for them. We don't want people dependent on the buggy, inconsistent behavior.

[sean-mcmanus]

@bobbrow I'm closing this PR for the reason Colen mentioned. It seems like we just need to inform users that the setting is intentionally deprecated and won't appear in the settings UI or json autocomplete for available settings.

[sean-mcmanus]

Plan is to re-added deprecation for 1.11.