Add note about refactoring

Co-Authored-By: Philipp Krones <hello@philkrones.com>

clippy_lints/src/misc_early.rs

@@ -199,6 +199,10 @@ declare_clippy_lint! {
     /// **What it does:** Checks for tuple patterns with a wildcard
     /// pattern (`_`) is next to a rest pattern (`..`).
     ///
+    /// _NOTE_: While `_, ..` means there is at least one element left, `..`
+    /// means there are 0 or more elements left. This can make a difference
+    /// when refactoring, but shouldn't result in errors in the refactored code,
+    /// since the wildcard pattern isn't used anyway.
     /// **Why is this bad?** The wildcard pattern is unneeded as the rest pattern
     /// can match that element as well.
     ///