chore(dsm): Add separator before type suffix in integer literals.

[daniel-wong-dfinity-org]

E.g. 42u64 is changed to 42_u64.

Why: Spaces good.

Why (long version): ThereisareasonthatspaceswereinventedinthefirstplacewhywedonotsimplywriteentireprogramsononelineItisbecausewhenshitiswrittenthiswayitisprofoundlyunreadabledespitetakingupmuchlessspaceSpacesarenotsomeextravaganceTheyareinfactvitaltogoodhumancomprehensionAndthatisalwaysourgoaltooptimizeFORTHEREADERYouarewelcomeforthemigrainethatthisstatementisinducingLetitbeavaluablelessontoyouaboutthenonextravagenceofspacesNowgoforthandusespacejudiciouslyorelsetherobotswillcomeknockingatyourdoorverysoon

Fix stats: ~370 literals, 68 files

How to re-create these changes:

1. Build the tool. It is not in master yet; rather, it is in review in PR 9418. Until that happens, you'll first need to check out add-integer-type-suffix-separator-tool-daniel-wong. Then, bazel build //rs/tools/add-integer-type-suffix-separator.

2. Then, check out the master commit that this is based on (originally, 40ad82dbd8) and run the tool against all directories owned by Deterministic State Machine team.

for DIRECTORY in \
    rs/canister_sandbox \
    rs/canonical_state \
    rs/cycles_account_manager \
    rs/determinism_test \
    rs/embedders \
    rs/execution_environment \
    rs/memory_tracker \
    rs/messaging \
    rs/migration_canister \
    rs/pocket_ic_server \
    rs/query_stats \
    rs/replica_tests \
    rs/replicated_state \
    rs/rust_canisters/backtrace_canister \
    rs/rust_canisters/call_loop_canister \
    rs/rust_canisters/call_tree_test \
    rs/rust_canisters/canister_creator \
    rs/rust_canisters/load_simulator \
    rs/rust_canisters/memory_test \
    rs/rust_canisters/messaging_test \
    rs/rust_canisters/response_payload_test \
    rs/rust_canisters/stable_memory_integrity \
    rs/rust_canisters/stable_structures \
    rs/rust_canisters/statesync_test \
    rs/rust_canisters/xnet_test \
    rs/state_layout \
    rs/state_machine_tests \
    rs/state_manager \
    rs/state_tool \
    rs/sys \
    rs/test_utilities/embedders \
    rs/test_utilities/execution_environment \
    rs/test_utilities/state \
    rs/tests/execution \
    rs/tests/message_routing \
    rs/tree_deserializer \
    rs/types/management_canister_types \
    rs/types/wasm_types \
    rs/universal_canister \
    rs/utils/lru_cache \
    rs/utils/thread \
    rs/xnet \
    rs/crypto/tree_hash \
    rs/query_stats \
    rs/tests/query_stats
do
    ./bazel-bin/rs/tools/add-integer-type-suffix-separator/add-integer-type-suffix-separator $DIRECTORY
done

[alin-at-dfinity]

LGTM, thank you.

[fspreiss]

The PR description says what is done and how it is done, but it doesn't say why it is done.

[fspreiss]

@daniel-wong-dfinity-org, how about using a clippy lint instead? https://rust-lang.github.io/rust-clippy/master/?search=unsepa#unseparated_literal_suffix

[daniel-wong-dfinity-org]

Why

Updated. I thought the rationale goes without saying.

unseparated_literal_suffix

Before we can enforce that 42u64 is disallowed, we have to make existing code compliant. This is part of that.

But yes, unseparated_literal_suffix is the right way to enforce. We just cannot start enforcing yet, because we have (lots of) non-compliant code. Enforcement will be turned on (by PR 9452) in the near future, once all non-compliant code is fixed.