I.10: structured bindings is now available (#1442)

- C++17 is already available
- synchronize with F.21:
  - put quotes around "structured bindings"
  - remove link to proposal

CppCoreGuidelines.md

@@ -1790,7 +1790,7 @@ If you can't use exceptions (e.g., because your code is full of old-style raw-po
     // ... use val ...
 
 This style unfortunately leads to uninitialized variables.
-A facility [structured bindings](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0144r1.pdf) to deal with that will become available in C++17.
+Since C++17 the "structured bindings" feature can be used to initialize variables directly from the return value:
 
     auto [val, error_code] = do_something();
     if (error_code) {