Remove deprecated enforceEx

[MoonlightSentinel]

Extracted from #7280 and blocked by:

• Remove imports of deprecated enforceEx vibe-d/vibe.d#2388
• new vibe-d release

[n8sh]

This is a fine example of why deprecations of this kind are bad.

Change Log: 2.080.0

std.exception.enforceEx was deprecated in favor of std.exception.enforce
With 2.079 std.exception.enforce became a complete super set of std.exception.enforceEx

enforce behaves exactly the same as enforceEx given the same arguments. The name std.exception.enforceEx isn't misleading and there are no plans to reuse it to mean something else. The best approach would have been to write

/// Legacy alias for `enforce`.
alias enforceEx = enforce

and never speak of it again.

[MoonlightSentinel]

I wouldn't mind keeping a legacy alias but it was already scheduled for removal and would probably need some formal approval (akin to adding a new symbol).

One might argue that introducing this could introduce hidden behaivour changes in highly templated code because enforce is a superset of enforceEx (allthough this is propably a very hypothetical case)

[MoonlightSentinel]

Closing in favour of #7545