chore: refresh dependencies and CI coverage

[DCjanus]

Why

• Refresh the dependency stack around the current Tantivy tokenizer API.
• Keep CI coverage, README examples, and release checks aligned with the updated crate.

What

• Update tantivy to 0.26.1, jieba-rs to 0.9.0, log to 0.4.29, and flexi_logger to 0.31.8.
• Bump this crate to 0.19.0 and adapt tests for Tantivy 0.26 API changes.
• Run the README usage snippet as a doctest.
• Add Codecov coverage upload with cargo llvm-cov; the coverage job now covers the stable test lane.
• Skip duplicate cargo-test execution in the CI lint job.

Breaking Change

• This crate now targets tantivy 0.26.
• Downstream users should update their Tantivy dependency and adapt related Tantivy API usage.

Validation

• prek run --all-files
• cargo test --doc
• rustup run 1.88.0 cargo test --workspace
• cargo llvm-cov --workspace --lcov --output-path lcov.info
• cargo publish --dry-run --allow-dirty
• GitHub Actions: test, lint, coverage, and publish-dry-run

[Copilot]

Pull request overview

This PR refreshes the crate’s Tantivy integration to the current tantivy 0.26 line, updating the dependency stack and aligning tests/docs with the updated Tantivy APIs.

Changes:

• Bumped crate version and updated core dependencies (notably tantivy 0.22 -> 0.26, plus jieba-rs, log, flexi_logger).
• Updated tests for Tantivy 0.26 collector and snippet API changes (explicit TopDocs ordering; new SnippetGenerator import path).
• Made the README usage snippet runnable as a Rust doctest by including README.md as crate docs and wrapping the example in fn main() -> tantivy::Result<()>.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
Cargo.toml	Updates crate version and bumps Tantivy/Jieba/logging dependencies to newer releases.
tests/unicode_split.rs	Adjusts TopDocs usage to comply with Tantivy 0.26’s explicit ordering requirement.
tests/position.rs	Updates TopDocs ordering and SnippetGenerator import path for Tantivy 0.26.
src/lib.rs	Includes README.md as crate-level docs so the README example is exercised via doctests.
README.md	Wraps the usage snippet in a main returning tantivy::Result so it can run as a doctest.
.github/workflows/ci.yml	Skips cargo-test in the lint job’s prek run (tests still run in the separate matrix job).

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[codecov]

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.