Fix typo

Author: sjwang05

clippy_lints/src/manual_option_folding.rs

@@ -23,7 +23,7 @@ declare_clippy_lint! {
     /// ```
     /// Use instead:
     /// ```rust
-    /// let opt = Option<i32> = None;
+    /// let opt: Option<i32> = None;
     /// let res: i32 = foo().unwrap_or(42);
     /// ```
     #[clippy::version = "1.74.0"]