message: [SwiftASTContext] Minor cleanups for GetTypeFromMangledTypename.
  > Reduce indentation for slightly easier readability.
  > Use the correct mangling prefix in the error ($S and not _T)
  > Remove else after return as it's not needed.
diff: @@ -3863,8 +3863,14 @@ SwiftASTContext::GetTypeFromMangledTypename(const char *mangled_typename,
  Status &error) {
  VALID_OR_RETURN(CompilerType());
  - if (mangled_typename
  - && SwiftLanguageRuntime::IsSwiftMangledName(mangled_typename)) {
  + if (!mangled_typename ||
  + !SwiftLanguageRuntime::IsSwiftMangledName(mangled_typename)) {
  + error.SetErrorStringWithFormat("typename '%s' is not a valid Swift mangled "
  + "typename, it should begin with $S",
  + mangled_typename);
  + return CompilerType();
  + }
  +
  Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_TYPES));
  if (log)
  log->Printf("((SwiftASTContext*)%p)->GetTypeFromMangledTypename('%s')",
  @@ -3923,7 +3929,7 @@ SwiftASTContext::GetTypeFromMangledTypename(const char *mangled_typename,
  this, mangled_typename,
  result_type.GetTypeName().GetCString());
  return result_type;
  - } else {
  + }
  if (log)
  log->Printf("((SwiftASTContext*)%p)->GetTypeFromMangledTypename('%s') "
  "-- error: %s",
  @@ -3934,12 +3940,6 @@ SwiftASTContext::GetTypeFromMangledTypename(const char *mangled_typename,
  CacheDemangledTypeFailure(mangled_name.GetCString());
  return CompilerType();
  }
  - }
  - error.SetErrorStringWithFormat("typename '%s' is not a valid Swift mangled "
  - "typename, it should begin with _T",
  - mangled_typename);
  - return CompilerType();
  -}
  CompilerType SwiftASTContext::GetVoidFunctionType() {
  VALID_OR_RETURN(CompilerType());
  