docs: private static int checkFormalTypeParameter(final String signature, int pos) {
          // FormalTypeParameter:
          // Identifier : FieldTypeSignature? (: FieldTypeSignature)*
  
          pos = checkIdentifier(signature, pos);
          pos = checkChar(':', signature, pos);
          if ("L[T".indexOf(getChar(signature, pos)) != -1) {
              pos = checkFieldTypeSignature(signature, pos);
          }
          while (getChar(signature, pos) == ':') {
              pos = checkFieldTypeSignature(signature, pos + 1);
          }
          return pos;
      }