nit: change placeholders

Author: wowinter13

clippy_lints/src/methods/sliced_string_as_bytes.rs

@@ -14,8 +14,8 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>) {
         && (ty.is_str() || is_type_lang_item(cx, ty, LangItem::String))
     {
         let mut applicability = Applicability::MaybeIncorrect;
-        let stringish = snippet_with_applicability(cx, indexed.span, "..", &mut applicability);
-        let range = snippet_with_applicability(cx, index.span, "..", &mut applicability);
+        let stringish = snippet_with_applicability(cx, indexed.span, "_", &mut applicability);
+        let range = snippet_with_applicability(cx, index.span, "_", &mut applicability);
         span_lint_and_sugg(
             cx,
             SLICED_STRING_AS_BYTES,