[clang] [clang-format] Remove code related to trigraphs (PR #148640)

[Owen Pan via cfe-commits]

================
@@ -1300,22 +1293,16 @@ FormatToken *FormatTokenLexer::getNextToken() {
             Style.TabWidth - (Style.TabWidth ? Column % Style.TabWidth : 0);
         break;
       case '\\':
-      case '?':
-      case '/':
-        // The text was entirely whitespace when this loop was entered. Thus
-        // this has to be an escape sequence.
-        assert(Text.substr(i, 4) == "\?\?/\r" ||
-               Text.substr(i, 4) == "\?\?/\n" ||
-               (i >= 1 && (Text.substr(i - 1, 4) == "\?\?/\r" ||
-                           Text.substr(i - 1, 4) == "\?\?/\n")) ||
-               (i >= 2 && (Text.substr(i - 2, 4) == "\?\?/\r" ||
-                           Text.substr(i - 2, 4) == "\?\?/\n")) ||
-               (Text[i] == '\\' && [&]() -> bool {
-                 size_t j = i + 1;
-                 while (j < Text.size() && isHorizontalWhitespace(Text[j]))
-                   ++j;
-                 return j < Text.size() && (Text[j] == '\n' || Text[j] == '\r');
-               }()));
+        // The code preceding the loop and in the countLeadingWhitespace
+        // function guarantees that Text is entirely whitespace, not including
+        // comments but including escaped newlines. So if 1 of these characters
+        // show up, then it has to be in an escape sequence.
+        assert(Text[i] == '\\' && [&]() -> bool {
----------------
owenca wrote:

```suggestion
        assert([&]() -> bool {
```

https://github.com/llvm/llvm-project/pull/148640