Add group for sending-closure-risks-data-race.md

Also adds a parent `RegionIsolation` group to link both
`SendingRisksDataRace` and the newly added
`SendingClosureRisksDataRace`.

Author: bnbarham

include/swift/AST/DiagnosticGroups.def

@@ -69,10 +69,12 @@ GROUP(PerformanceHints, "performance-hints")
 GROUP(PreconcurrencyImport, "preconcurrency-import")
 GROUP(PropertyWrappers, "property-wrapper-requirements")
 GROUP(ProtocolTypeNonConformance, "protocol-type-non-conformance")
+GROUP(RegionIsolation, "region-isolation")
 GROUP(ResultBuilderMethods, "result-builder-methods")
 GROUP(ReturnTypeImplicitCopy, "return-type-implicit-copy")
 GROUP(SendableClosureCaptures, "sendable-closure-captures")
 GROUP(SendableMetatypes, "sendable-metatypes")
+GROUP(SendingClosureRisksDataRace, "sending-closure-risks-data-race")
 GROUP(SendingRisksDataRace, "sending-risks-data-race")
 GROUP(StrictLanguageFeatures, "strict-language-features")
 GROUP(StrictMemorySafety, "strict-memory-safety")
@@ -85,5 +87,8 @@ GROUP(WeakMutability, "weak-mutability")
 GROUP_LINK(PerformanceHints, ExistentialType)
 GROUP_LINK(PerformanceHints, ReturnTypeImplicitCopy)
 
+GROUP_LINK(RegionIsolation, SendingClosureRisksDataRace)
+GROUP_LINK(RegionIsolation, SendingRisksDataRace)
+
 #define UNDEFINE_DIAGNOSTIC_GROUPS_MACROS
 #include "swift/AST/DefineDiagnosticGroupsMacros.h"

include/swift/AST/DiagnosticsSIL.def

@@ -1075,7 +1075,7 @@ NOTE(regionbasedisolation_typed_tns_passed_to_sending, none,
      "causing races inbetween %0 uses and uses reachable from the callee",
      (StringRef, Type))
 
-ERROR(regionbasedisolation_typed_tns_passed_sending_closure, none,
+GROUPED_ERROR(regionbasedisolation_typed_tns_passed_sending_closure, SendingClosureRisksDataRace, none,
      "passing closure as a 'sending' parameter risks causing data races between %0 and concurrent execution of the closure",
      (StringRef))
 NOTE(regionbasedisolation_typed_tns_passed_to_sending_closure_helper_have_value, none,