update documentation for cast

Author: navh

clippy_lints/src/casts/mod.rs

@@ -80,12 +80,13 @@ declare_clippy_lint! {
     /// ### What it does
     /// Checks for casts between numerical types that may
     /// truncate large values. This is expected behavior, so the cast is `Allow` by
-    /// default.
+    /// default. This lint prompts user to either allow the lint if truncation is desired,
+    /// or suggests using `try_from` and handling the error.
     ///
     /// ### Why is this bad?
     /// In some problem domains, it is good practice to avoid
     /// truncation. This lint can be activated to help assess where additional
-    /// checks could be beneficial, and suggests implementing TryFrom trait.
+    /// checks could be beneficial.
     ///
     /// ### Example
     /// ```rust

src/docs/cast_possible_truncation.txt

@@ -1,12 +1,13 @@
 ### What it does
 Checks for casts between numerical types that may
 truncate large values. This is expected behavior, so the cast is `Allow` by
-default.
+default. This lint prompts user to either allow the lint if truncation is desired,
+or suggests using `try_from` and handling the error.
 
 ### Why is this bad?
 In some problem domains, it is good practice to avoid
 truncation. This lint can be activated to help assess where additional
-checks could be beneficial, and suggests implementing TryFrom trait.
+checks could be beneficial.
 
 ### Example
 ```