Update applicability messages for clarity in tests (#8541)

These names are only ever displayed internally right now and we could be
clearer in our test snapshots.

The diff is kind of scary because all of the tests fixtures are updated.

crates/ruff_linter/src/message/diff.rs

@@ -54,9 +54,9 @@ impl Display for Diff<'_> {
 
         let message = match self.fix.applicability() {
             // TODO(zanieb): Adjust this messaging once it's user-facing
-            Applicability::Safe => "Fix",
-            Applicability::Unsafe => "Suggested fix",
-            Applicability::Display => "Possible fix",
+            Applicability::Safe => "Safe fix",
+            Applicability::Unsafe => "Unsafe fix",
+            Applicability::DisplayOnly => "Display-only fix",
         };
         writeln!(f, "ℹ {}", message.blue())?;