Apply suggestions from code review

Co-authored-by: Michael Buch <[email protected]>

Author: charles-zablit

lldb/source/Plugins/Language/Swift/SwiftLanguage.cpp

@@ -1754,14 +1754,14 @@ bool SwiftLanguage::GetFunctionDisplayName(
 std::string SwiftLanguage::GetFunctionName(const SymbolContext &sc,
                                            const ExecutionContext *exe_ctx) {
   if (!sc.function)
-    return "";
+    return {};
   if (sc.function->GetLanguage() != eLanguageTypeSwift)
-    return "";
+    return {};
   std::string name = SwiftLanguageRuntime::DemangleSymbolAsString(
       sc.function->GetMangled().GetMangledName().GetStringRef(),
       SwiftLanguageRuntime::eSimplified, &sc, exe_ctx);
   if (name.empty())
-    return "";
+    return {};
   const char *cstr = name.data();
   const char *open_paren = strchr(cstr, '(');
   const char *generic = strchr(cstr, '<');