docs: clarify --full-path help text (fixes #1686)

[wyf027]

Summary

Clarifies --full-path / -p documentation so users understand:

• By default, patterns match the last path component (not "filename only" / ambiguous "full path").
• With -p, patterns match the absolute path (not a relative path from the search root).

Updates src/cli.rs, doc/fd.1, README.md (prose + --help snapshot), zsh completion, and an internal comment in src/config.rs.

Fixes #1686.

Context

Follows feedback on #1996 from @tmccombs:

• Keep absolute in the description of what -p matches (see also --abs-path and --rel-path instead of --full-path #839).
• Prefer last path component over "final" / "filename only" for the default behavior.

Checks

• cargo fmt -- --check
• cargo clippy --all-targets --all-features -- -Dwarnings
• cargo test --locked

[wyf027]

Hi maintainers — gentle ping on this docs-only PR.

It addresses #1686 and incorporates the review feedback from #1996 (@tmccombs): use absolute path for -p matching and last path component for the default (see also #839).

All CI checks are green on my side. Happy to tweak wording or close this in favor of #1996 if you prefer that PR updated instead.

Thanks!

[wyf027]

Gentle ping — docs-only PR, all CI green. Ready for review when you have a moment. Thanks!

[wyf027]

Still green and ready for review. Happy to adjust wording if needed.

[wyf027]

Added regression test test_full_path_help_text (checks fd -h for the updated -p help line).

CI re-running on the latest push — still ready for review. Thanks!

[wyf027]

Pushed a follow-up: test_full_path_help_text now resolves the fd binary the same way as other integration tests (CARGO_BIN_EXE_fd env var with env!("CARGO_BIN_EXE_fd") fallback), fixing the MSRV job. CI is green on my side.

[wyf027]

Friendly ping — CI green, incorporates feedback from #1996 review. Ready when you have time. Thanks!

[tmccombs]

I don't think we need a test for the help text

[tmccombs]

probably also worth adding an entry to the changelog