Remove always-on language feature flag: ErrorOnDeprecatedRequireQualifiedAccess

[T-Gro]

LanguageFeature.ErrorOnDeprecatedRequireQualifiedAccess has shipped since F# 7.0 and is enabled for every selectable language version (the minimum accepted --langversion is 8.0). Its feature flag can therefore never be turned off, so it is dead configuration. This issue removes the flag and collapses the guarded code to its enabled behaviour.

What to remove

• The ErrorOnDeprecatedRequireQualifiedAccess case in LanguageFeatures.fs and LanguageFeatures.fsi
• Its entry in the features map and its GetFeatureString arm
• The featureErrorOnDeprecatedRequireQualifiedAccess string in FSComp.txt
• Every SupportsFeature LanguageFeature.ErrorOnDeprecatedRequireQualifiedAccess / checkLanguageFeatureAndRecover … ErrorOnDeprecatedRequireQualifiedAccess guard — keep only the enabled path and delete the legacy branch
• Adjust affected tests and baselines accordingly

Consequence: --disableLanguageFeature:ErrorOnDeprecatedRequireQualifiedAccess is no longer a recognised feature name.

Version mapping

fsharp/src/Compiler/Facilities/LanguageFeatures.fs

Line 191 in ea778bb

LanguageFeature.ErrorOnDeprecatedRequireQualifiedAccess, languageVersion70

Feature string

fsharp/src/Compiler/FSComp.txt

Line 1588 in ea778bb

featureErrorOnDeprecatedRequireQualifiedAccess,"give error on deprecated access of construct with RequireQualifiedAccess attribute"

Part of #20139