Fix C++ ifndef_guard printer to also convert "-" to "_".

PiperOrigin-RevId: 679648401

src/google/protobuf/compiler/cpp/ifndef_guard.cc

@@ -30,6 +30,7 @@ std::string MakeIfdefGuardIdentifier(const absl::string_view header_path) {
                                                                 {
                                                                     {"/", "_"},
                                                                     {".", "_"},
+                                                                    {"-", "_"},
                                                                 })),
                       "_");
 }

src/google/protobuf/compiler/cpp/ifndef_guard_unittest.cc

@@ -36,7 +36,7 @@ TEST_F(IfnDefGuardTest, Basic) {
   {
     io::Printer printer(output(), '$');
 
-    const IfdefGuardPrinter ifdef_guard(&printer, "A/B/E/alpha");
+    const IfdefGuardPrinter ifdef_guard(&printer, "A/B-E.alpha");
 
     EXPECT_FALSE(printer.failed());
   }