Renaming [block_id] into [label].

examples/proofs/btree/generated_proof_btree_member.v

examples/proofs/btree/generated_proof_free_btree.v

examples/proofs/btree/generated_proof_key_index.v

examples/proofs/btree/generated_proof_new_btree.v

examples/proofs/latch/generated_proof_latch_release.v

examples/proofs/latch/generated_proof_latch_wait.v

examples/proofs/lock/generated_proof_increment.v

examples/proofs/lock/generated_proof_init.v

examples/proofs/lock/generated_proof_read_locked.v

examples/proofs/lock/generated_proof_read_outside.v

examples/proofs/lock/generated_proof_write_locked.v

examples/proofs/lock/generated_proof_write_outside.v

examples/proofs/malloc1/generated_proof_slab_alloc.v

examples/proofs/malloc1/generated_proof_slab_free.v

examples/proofs/malloc1/generated_proof_slab_init.v

examples/proofs/mpool/generated_proof_mpool_add_chunk.v

examples/proofs/mpool/generated_proof_mpool_alloc.v

...les/proofs/mpool/generated_proof_mpool_alloc_contiguous.v

...pool/generated_proof_mpool_alloc_contiguous_no_fallback.v

...es/proofs/mpool/generated_proof_mpool_alloc_no_fallback.v