Googletest export

Update note on static const data members for C++17.

Using `constexpr` provides a tidier solution, where applicable.

PiperOrigin-RevId: 343276402

googletest/docs/faq.md

@@ -217,6 +217,18 @@ particular, using it in googletest comparison assertions (`EXPECT_EQ`, etc) will
 generate an "undefined reference" linker error. The fact that "it used to work"
 doesn't mean it's valid. It just means that you were lucky. :-)
 
+If the declaration of the static data member is `constexpr` then it is
+implicitly an `inline` definition, and a separate definition in `foo.cc` is not
+needed:
+
+```c++
+// foo.h
+class Foo {
+  ...
+  static constexpr int kBar = 100;  // Defines kBar, no need to do it in foo.cc.
+};
+```
+
 ## Can I derive a test fixture from another?
 
 Yes.