Merge pull request #21195 from jketema/jketema/embed

C++: Support C23/C++26 `#embed` preprocessor directives

Author: jketema

cpp/downgrades/9439176c1d1312787926458dd54d65a849069118/old.dbscheme

@@ -0,0 +1,13 @@
+class PreprocessorDirective extends @preprocdirect {
+  string toString() { none() }
+}
+
+class Location extends @location_default {
+  string toString() { none() }
+}
+
+from PreprocessorDirective ppd, int kind, int kind_new, Location l
+where
+  preprocdirects(ppd, kind, l) and
+  if kind = 17 then kind_new = /* ppd_warning */ 18 else kind_new = kind
+select ppd, kind_new, l