Update C Defect Report Status

https://clang.llvm.org/c_dr_status.html

There is a new issues list at https://www.open-std.org/jtc1/sc22/wg14/issues/, should the links here be updated to use this instead? There are also new issues for C23, though these are not called defect reports anymore.

There is also a typo "constan expression" which should be "constant expression".

Start by locating the source for the page at clang.llvm.org/c_dr_status.html and compare its links with the WG14 issues list at open-std.org/jtc1/sc22/wg14/issues/. Update the relevant links and C23 wording, correct “constan expression” to “constant expression,” and verify the rendered page contains the intended references.

Written by the indexing model from the issue text.