Merge pull request #22816 from jketema/jketema/bitint

C++: Add support for C23 `_BitInt`s

Author: jketema

cpp/downgrades/6aec212e408fad907b19368a3376a4d9837783d2/builtintypes.ql

@@ -0,0 +1,9 @@
+class BuiltInType extends @builtintype {
+  string toString() { none() }
+}
+
+from BuiltInType type, string name, int kind, int kind_new, int size, int sign, int alignment
+where
+  builtintypes(type, name, kind, size, sign, alignment) and
+  if kind in [67, 68, 69] then kind_new = 1 else kind_new = kind
+select type, name, kind_new, size, sign, alignment