Fix vi replace with v

[catlover-bot]

Summary

Fix vi normal-mode r<char> replacement when the replacement character is v.

Before

After pressing r in vi normal mode, pressing v entered visual mode instead of completing the pending replace command.

The special-case handling for v ran before the pending multi-key command could consume it.

After

v enters visual mode only when there is no pending vi command. When r is already pending, v is consumed as the replacement character and produces ReplaceChar('v').

A regression test covers the rv sequence while preserving the existing standalone v behavior.

Additional notes

Fixes #1159.

Validation:

• cargo test edit_mode::vi:: -- --nocapture — 148 passed
• cargo fmt --all -- --check
• cargo clippy --locked --all-targets --all-features
• cargo test --all --all-features -- --test-threads=1 — 1525 passed, 1 ignored; 30 doctests passed
• git diff --check

[kronberger-droid]

Looks good.

Some things I would maybe do before we land this:

• remove the self.cache.clear() since its now a no-op
• 2v stops entering visual mode, which should at least be documented with a TODO comment and in the PR body.
• you actually also fix fv and tv. Maybe mention it in the body and add some tests for it.

Thanks for handling this.