[Diag]: Result builder misplacement error message mentions subscript

Author: saehejkang

include/swift/AST/DiagnosticsSema.def

@@ -7263,7 +7263,7 @@ NOTE(note_result_builder_control_flow, none,
       "builder %0", (DeclName))
 ERROR(result_builder_attribute_not_allowed_here, none,
       "result builder attribute %0 can only be applied to a parameter, "
-      "function, or computed property", (Identifier))
+      "function, subscript, or computed property", (Identifier))
 ERROR(result_builder_attribute_on_storage_without_getter, none,
       "result builder attribute %0 can only be applied to a "
       "%select{subscript|property|constant|variable}1 if it defines a getter",

test/decl/var/result_builders.swift

@@ -12,7 +12,7 @@ struct Maker {} // expected-error {{result builder must provide at least one sta
 @resultBuilder
 class Inventor {} // expected-error {{result builder must provide at least one static 'buildBlock' method}}
 
-@Maker // expected-error {{result builder attribute 'Maker' can only be applied to a parameter, function, or computed property}}
+@Maker // expected-error {{result builder attribute 'Maker' can only be applied to a parameter, function, subscript, or computed property}}
 typealias typename = Inventor
 
 @Maker // expected-error {{result builder attribute 'Maker' can only be applied to a variable if it defines a getter}}