Rewrite a variety of .contains() calls as matches! statements (#5432)

## Summary

These have the potential to be much more efficient, as we've seen in the
past.

crates/ruff_python_stdlib/src/future.rs

@@ -1,13 +1,17 @@
-/// A copy of `__future__.all_feature_names`.
-pub const ALL_FEATURE_NAMES: &[&str] = &[
-    "nested_scopes",
-    "generators",
-    "division",
-    "absolute_import",
-    "with_statement",
-    "print_function",
-    "unicode_literals",
-    "barry_as_FLUFL",
-    "generator_stop",
-    "annotations",
-];
+/// Returns `true` if `name` is a valid `__future__` feature name, as defined by
+/// `__future__.all_feature_names`.
+pub fn is_feature_name(name: &str) -> bool {
+    matches!(
+        name,
+        "nested_scopes"
+            | "generators"
+            | "division"
+            | "absolute_import"
+            | "with_statement"
+            | "print_function"
+            | "unicode_literals"
+            | "barry_as_FLUFL"
+            | "generator_stop"
+            | "annotations"
+    )
+}