Removed an old TODO comment

src/include/units/physical/si/temperature.h

@@ -38,7 +38,7 @@ inline namespace literals {
 
 // K
 constexpr auto operator"" q_K(unsigned long long l) { return temperature<kelvin, std::int64_t>(l); }
-constexpr auto operator"" q_K(long double l) { return temperature<kelvin, long double>(l); }   // TODO: conflicts with gcc GNU extension
+constexpr auto operator"" q_K(long double l) { return temperature<kelvin, long double>(l); }
 
 }  // namespace literals