Add #![warn(clippy::pedantic)] to lib.rs and main.rs files

We already enforced pedantic clippy lints via the
following command in .github/workflows/ci.yaml:

    cargo clippy --workspace --all-targets --all-features -- -D warnings -W clippy::pedantic

Additionally adding #![warn(clippy::pedantic)] to all main.rs and lib.rs
has the benefit that violations of pedantic clippy lints are also
reported when just running `cargo clippy` without any arguments and
are thereby also picked up by LSP[1] servers such as rust-analyzer[2].
However for rust-analyzer to run clippy you'll have to configure:

    "rust-analyzer.check.command": "clippy",

in your editor.[3]

[1]: https://microsoft.github.io/language-server-protocol/
[2]: https://rust-analyzer.github.io/
[3]: https://rust-analyzer.github.io/manual.html#configuration

CONTRIBUTING.md

@@ -46,7 +46,7 @@ For rustfmt and Clippy, we use [nightly Rust][nightly], as it is stricter than s
 
 ```shell
 cargo +nightly fmt --all     # Auto-formatting...
-cargo +nightly clippy --fix --workspace --all-targets --all-features -- -W clippy::pedantic  # Linting...
+cargo +nightly clippy --fix --workspace --all-targets --all-features  # Linting...
 cargo test --all    # Testing...
 ```
 

flake8_to_ruff/src/main.rs

@@ -1,5 +1,6 @@
 //! Utility to generate Ruff's `pyproject.toml` section from a Flake8 INI file.
 #![forbid(unsafe_code)]
+#![warn(clippy::pedantic)]
 #![allow(
     clippy::collapsible_else_if,
     clippy::collapsible_if,

ruff_cli/src/lib.rs

@@ -3,6 +3,7 @@
 //!
 //! For the actual Ruff library, see [`ruff`].
 #![forbid(unsafe_code)]
+#![warn(clippy::pedantic)]
 #![allow(clippy::must_use_candidate, dead_code)]
 
 mod cli;

ruff_cli/src/main.rs

@@ -1,4 +1,5 @@
 #![forbid(unsafe_code)]
+#![warn(clippy::pedantic)]
 #![allow(
     clippy::match_same_arms,
     clippy::missing_errors_doc,

ruff_dev/src/main.rs

@@ -2,6 +2,7 @@
 //!
 //! Within the ruff repository you can run it with `cargo dev`.
 #![forbid(unsafe_code)]
+#![warn(clippy::pedantic)]
 #![allow(
     clippy::collapsible_else_if,
     clippy::collapsible_if,

ruff_macros/src/lib.rs

@@ -1,5 +1,6 @@
 //! This crate implements internal macros for the `ruff` library.
 #![forbid(unsafe_code)]
+#![warn(clippy::pedantic)]
 #![allow(
     clippy::collapsible_else_if,
     clippy::collapsible_if,

src/lib.rs

@@ -5,6 +5,7 @@
 //!
 //! [Ruff]: https://github.com/charliermarsh/ruff
 #![forbid(unsafe_code)]
+#![warn(clippy::pedantic)]
 #![allow(
     clippy::collapsible_else_if,
     clippy::collapsible_if,