Add a bit more testing

Author: grynspan

Sources/TestingMacros/Support/DiagnosticMessage.swift

@@ -655,7 +655,6 @@ struct DiagnosticMessage: SwiftDiagnostics.DiagnosticMessage {
     fromArgument argumentContainingDisplayName: LabeledExprListSyntax.Element,
     using attribute: AttributeSyntax
   ) -> Self {
-    // FIXME: implement fixits
     Self(
       syntax: Syntax(decl),
       message: "Attribute \(_macroName(attribute)) specifies display name '\(displayNameFromAttribute.representedLiteralValue!)' for \(_kindString(for: decl)) with implicit display name '\(decl.name.rawIdentifier!)'",

Tests/TestingTests/MiscellaneousTests.swift

@@ -290,6 +290,10 @@ struct MiscellaneousTests {
   @Test func `__raw__$raw_identifier_provides_a_display_name`() throws {
     let test = try #require(Test.current)
     #expect(test.displayName == "raw_identifier_provides_a_display_name")
+    #expect(test.name == "`raw_identifier_provides_a_display_name`()")
+    let id = test.id
+    #expect(id.moduleName == "TestingTests")
+    #expect(id.nameComponents == ["MiscellaneousTests", "`raw_identifier_provides_a_display_name`()"])
   }
 
   @Test("Free functions are runnable")