Fix cast insertion in the front end.

1 job for ci/frontent_fix in 14 minutes and 34 seconds (queued for 1 second)
Name Stage Failure
build-coq.8.12.0 Build

File "./tutorial/proofs/t11_tree_set/generated_proof_remove.v", line 31, characters 2-6:
Error: (in proof type_remove): Attempt to save a proof with given up goals.
If this is really what you want to do, use Admitted in place of Qed.

Makefile:6: recipe for target 'all_with_examples' failed
make: *** [all_with_examples] Error 1
ERROR: Job failed: exit code 1