Refactored some string handling to prevent ICEs and FNs

tests/ui/crashes/ice-7869.rs

@@ -0,0 +1,7 @@
+enum Tila {
+    TyöAlkoi,
+    TyöKeskeytyi,
+    TyöValmis,
+}
+
+fn main() {}

tests/ui/crashes/ice-7869.stderr

@@ -0,0 +1,15 @@
+error: all variants have the same prefix: `Työ`
+  --> $DIR/ice-7869.rs:1:1
+   |
+LL | / enum Tila {
+LL | |     TyöAlkoi,
+LL | |     TyöKeskeytyi,
+LL | |     TyöValmis,
+LL | | }
+   | |_^
+   |
+   = note: `-D clippy::enum-variant-names` implied by `-D warnings`
+   = help: remove the prefixes and use full paths to the variants instead of glob imports
+
+error: aborting due to previous error
+

tests/ui/enum_variants.stderr

@@ -60,7 +60,7 @@ LL | | }
    |
    = help: remove the prefixes and use full paths to the variants instead of glob imports
 
-error: all variants have the same prefix: `With`
+error: all variants have the same prefix: `WithOut`
   --> $DIR/enum_variants.rs:81:1
    |
 LL | / enum Seallll {

tests/ui/match_ref_pats.rs

@@ -1,5 +1,5 @@
 #![warn(clippy::match_ref_pats)]
-#![allow(clippy::equatable_if_let)]
+#![allow(clippy::equatable_if_let, clippy::enum_variant_names)]
 
 fn ref_pats() {
     {