Implement LWG#2063, and update the issues links to point to the github generated pages

llvm-svn: 249325
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 8428a9d5b6ba44228272eab5d9560054f61b65ce
diff --git a/include/string b/include/string
index 6ed4e74..46c749b 100644
--- a/include/string
+++ b/include/string
@@ -1509,6 +1509,7 @@
 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
     _LIBCPP_INLINE_VISIBILITY
     basic_string& assign(basic_string&& str)
+        _NOEXCEPT_((__noexcept_move_assign_container<_Allocator, __alloc_traits>::value))
         {*this = _VSTD::move(str); return *this;}
 #endif
     basic_string& assign(const basic_string& __str, size_type __pos, size_type __n=npos);