Revert "Add Doxygen injection into C and C++ comments" (#44883)

Reverts zed-industries/zed#43581

Release notes:
- Fixed comment injections not working with C and C++.

crates/languages/src/cpp/injections.scm

@@ -1,7 +1,6 @@
 ((comment) @injection.content
-  (#match? @injection.content "^(///|//!|/\\*\\*|/\\*!)(.*)")
-  (#set! injection.language "doxygen")
-  (#set! injection.include-children))
+ (#set! injection.language "comment")
+)
 
 (preproc_def
     value: (preproc_arg) @injection.content