Fix doc nits

CHANGELOG.md

@@ -5520,6 +5520,7 @@ Released 2018-09-13
 [`min_max`]: https://rust-lang.github.io/rust-clippy/master/index.html#min_max
 [`misaligned_transmute`]: https://rust-lang.github.io/rust-clippy/master/index.html#misaligned_transmute
 [`mismatched_target_os`]: https://rust-lang.github.io/rust-clippy/master/index.html#mismatched_target_os
+[`mismatched_target_os`]: https://rust-lang.github.io/rust-clippy/master/index.html#mismatched_target_os
 [`mismatching_type_param_order`]: https://rust-lang.github.io/rust-clippy/master/index.html#mismatching_type_param_order
 [`misnamed_getters`]: https://rust-lang.github.io/rust-clippy/master/index.html#misnamed_getters
 [`misrefactored_assign_op`]: https://rust-lang.github.io/rust-clippy/master/index.html#misrefactored_assign_op

clippy_lints/src/allow_attributes.rs

@@ -10,20 +10,19 @@ use rustc_session::declare_lint_pass;
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for usage of the `#[allow]` attribute and suggests replacing it with
-    /// the `#[expect]` (See [RFC 2383](https://rust-lang.github.io/rfcs/2383-lint-reasons.html))
+    /// `#[expect]`. (See [RFC 2383](https://rust-lang.github.io/rfcs/2383-lint-reasons.html))
     ///
-    /// The expect attribute is still unstable and requires the `lint_reasons`
+    /// The expect attribute is still unstable and requires the `lint_reasons` feature
     /// on nightly. It can be enabled by adding `#![feature(lint_reasons)]` to
     /// the crate root.
     ///
-    /// This lint only warns outer attributes (`#[allow]`), as inner attributes
+    /// This lint only warns on outer attributes (`#[allow]`), as inner attributes
     /// (`#![allow]`) are usually used to enable or disable lints on a global scale.
     ///
     /// ### Why restrict this?
-    /// `#[allow]` attributes can linger after their reason for existence is gone.
-    /// `#[expect]` attributes suppress the lint emission, but emit a warning if
-    /// the expectation is unfulfilled. This can be useful to be notified when the
-    /// lint is no longer triggered, which may indicate the attribute can be removed.
+    /// The `#[allow]` attribute does not warn when the expected lint is no longer triggered,
+    /// whereas `#[expect]` calls attention to this fact. This can be a useful reminder to
+    /// remove attributes that are no longer needed.
     ///
     /// ### Example
     /// ```rust,ignore

clippy_lints/src/arc_with_non_send_sync.rs

@@ -17,7 +17,7 @@ declare_clippy_lint! {
     /// `Arc<T>` is a thread-safe `Rc<T>` and guarantees that updates to the reference counter
     /// use atomic operations. To send an `Arc<T>` across thread boundaries and
     /// share ownership between multiple threads, `T` must be [both `Send` and `Sync`](https://doc.rust-lang.org/std/sync/struct.Arc.html#thread-safety),
-    /// so either `T` should be made `Send + Sync` or an `Rc` should be used instead of an `Arc`
+    /// so either `T` should be made `Send + Sync` or an `Rc` should be used instead of an `Arc`.
     ///
     /// ### Example
     /// ```no_run

clippy_lints/src/attrs/mod.rs

@@ -270,13 +270,49 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for attributes that allow lints without a reason.
+    /// Checks for cfg attributes having operating systems used in target family position.
     ///
-    /// (This requires the `lint_reasons` feature)
+    /// ### Why is this bad?
+    /// The configuration option will not be recognised and the related item will not be included
+    /// by the conditional compilation engine.
+    ///
+    /// ### Example
+    /// ```no_run
+    /// #[cfg(linux)]
+    /// fn conditional() { }
+    /// ```
+    ///
+    /// Use instead:
+    /// ```no_run
+    /// # mod hidden {
+    /// #[cfg(target_os = "linux")]
+    /// fn conditional() { }
+    /// # }
+    ///
+    /// // or
+    ///
+    /// #[cfg(unix)]
+    /// fn conditional() { }
+    /// ```
+    /// Check the [Rust Reference](https://doc.rust-lang.org/reference/conditional-compilation.html#target_os) for more details.
+    #[clippy::version = "1.45.0"]
+    pub MISMATCHED_TARGET_OS,
+    correctness,
+    "usage of `cfg(operating_system)` instead of `cfg(target_os = \"operating_system\")`"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for attributes that allow lints without specifying the reason
+    /// they should be allowed.
+    ///
+    /// (This requires the `lint_reasons` feature.)
     ///
     /// ### Why restrict this?
-    /// Justifying each `allow` helps readers understand the reasoning,
-    /// and may allow removing `allow` attributes if their purpose is obsolete.
+    /// There should always be a specific reason to allow a lint. This reason
+    /// should be documented using the `reason` parameter, so that readers can
+    /// understand why the `allow` is required, or remove it if it's no
+    /// longer needed.
     ///
     /// ### Example
     /// ```no_run

clippy_lints/src/declared_lints.rs

@@ -58,6 +58,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::attrs::EMPTY_LINE_AFTER_DOC_COMMENTS_INFO,
     crate::attrs::EMPTY_LINE_AFTER_OUTER_ATTR_INFO,
     crate::attrs::INLINE_ALWAYS_INFO,
+    crate::attrs::MISMATCHED_TARGET_OS_INFO,
     crate::attrs::MIXED_ATTRIBUTES_STYLE_INFO,
     crate::attrs::NON_MINIMAL_CFG_INFO,
     crate::attrs::SHOULD_PANIC_WITHOUT_EXPECT_INFO,

clippy_lints/src/loops/mod.rs

@@ -356,10 +356,10 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for loops which have a range bound that is a mutable variable
+    /// Checks for loops with a range bound that is a mutable variable.
     ///
     /// ### Why is this bad?
-    /// One might think that modifying the mutable variable changes the loop bounds
+    /// One might think that modifying the mutable variable changes the loop bounds. It doesn't.
     ///
     /// ### Known problems
     /// False positive when mutation is followed by a `break`, but the `break` is not immediately
@@ -381,7 +381,7 @@ declare_clippy_lint! {
     /// let mut foo = 42;
     /// for i in 0..foo {
     ///     foo -= 1;
-    ///     println!("{}", i); // prints numbers from 0 to 42, not 0 to 21
+    ///     println!("{i}"); // prints numbers from 0 to 41, not 0 to 21
     /// }
     /// ```
     #[clippy::version = "pre 1.29.0"]

clippy_lints/src/needless_for_each.rs

@@ -31,8 +31,8 @@ declare_clippy_lint! {
     /// Use instead:
     /// ```no_run
     /// let v = vec![0, 1, 2];
-    /// for elem in v.iter() {
-    ///     println!("{}", elem);
+    /// for elem in v {
+    ///     println!("{elem}");
     /// }
     /// ```
     ///