Improve docs

clippy_lints/src/len_zero.rs

@@ -7,13 +7,19 @@ use syntax::codemap::{Span, Spanned};
 use syntax::ptr::P;
 use utils::{get_item_name, in_macro, snippet, span_lint, span_lint_and_then, walk_ptrs_ty};
 
-/// **What it does:** This lint checks for getting the length of something via `.len()` just to compare to zero, and suggests using `.is_empty()` where applicable.
+/// **What it does:** This lint checks for getting the length of something via `.len()` just to
+/// compare to zero, and suggests using `.is_empty()` where applicable.
 ///
-/// **Why is this bad?** Some structures can answer `.is_empty()` much faster than calculating their length. So it is good to get into the habit of using `.is_empty()`, and having it is cheap. Besides, it makes the intent clearer than a comparison.
+/// **Why is this bad?** Some structures can answer `.is_empty()` much faster than calculating
+/// their length. So it is good to get into the habit of using `.is_empty()`, and having it is
+/// cheap. Besides, it makes the intent clearer than a comparison.
 ///
 /// **Known problems:** None
 ///
-/// **Example:** `if x.len() == 0 { .. }`
+/// **Example:**
+/// ```rust
+/// if x.len() == 0 { .. }
+/// ```
 declare_lint! {
     pub LEN_ZERO, Warn,
     "checking `.len() == 0` or `.len() > 0` (or similar) when `.is_empty()` \
@@ -22,12 +28,15 @@ declare_lint! {
 
 /// **What it does:** This lint checks for items that implement `.len()` but not `.is_empty()`.
 ///
-/// **Why is this bad?** It is good custom to have both methods, because for some data structures, asking about the length will be a costly operation, whereas `.is_empty()` can usually answer in constant time. Also it used to lead to false positives on the [`len_zero`](#len_zero) lint – currently that lint will ignore such entities.
+/// **Why is this bad?** It is good custom to have both methods, because for some data structures,
+/// asking about the length will be a costly operation, whereas `.is_empty()` can usually answer in
+/// constant time. Also it used to lead to false positives on the [`len_zero`](#len_zero) lint –
+/// currently that lint will ignore such entities.
 ///
 /// **Known problems:** None
 ///
 /// **Example:**
-/// ```
+/// ```rust
 /// impl X {
 ///     fn len(&self) -> usize { .. }
 /// }