Include proc macro crates in rust-project.json

These crates were skipped before, leaving dependencies missing in
rust-project.json. Include them and mark them as `"is_proc_macro": true`
so that rust-analyzer can process them.

Fixes: 202290038
Test: SOONG_GEN_RUST_PROJECT=1 m nothing
Change-Id: Ia80e6f5e2f56a76608ba057075600e6b4424281b