result.h - fix bugprone-suspicious-semicolon warning

Fixes:
  system/core/base/include/android-base/result.h:
  133:94: warning: potentially unintended semicolon [bugprone-suspicious-semicolon]

Bernie says:
  it probably means that there's a parser bug with "if constexpr"

  maybe, at static analysis pass, the "if constexpr" was evaluated to false,
  and the compiler removed the "then" block from the AST...
  ... and then it thought you had written it that way :-)
  https://reviews.llvm.org/D46027

Test: builds
Bug: 153035880
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I25df8eeca4ec06b3180c1cd21b554fc583c5581a

base/include/android-base/result.h

@@ -130,6 +130,7 @@ class Error {
 
   template <typename T>
   Error& operator<<(T&& t) {
+    // NOLINTNEXTLINE(bugprone-suspicious-semicolon)
     if constexpr (std::is_same_v<std::remove_cv_t<std::remove_reference_t<T>>, ResultError>) {
       errno_ = t.code();
       return (*this) << t.message();