tests: validate style_edition derivation

Adds a few tests that validate the various scenarios
of precendence, overrides, and defaults to ensure the
correct 'style_edition' value is selected even when
other options like 'edition' and/or 'version' are included.

tests/target/configs/indent_style/block_trailing_comma_call/one.rs

@@ -1,4 +1,4 @@
-// rustfmt-version: One
+// rustfmt-style_edition: 2015
 // rustfmt-error_on_line_overflow: false
 // rustfmt-indent_style: Block
 

tests/target/configs/indent_style/block_trailing_comma_call/two.rs

@@ -1,4 +1,4 @@
-// rustfmt-version: Two
+// rustfmt-style_edition: 2024
 // rustfmt-error_on_line_overflow: false
 // rustfmt-indent_style: Block
 

tests/target/configs/version/mapped.rs

@@ -0,0 +1,9 @@
+// rustfmt-version: Two
+fn main() {
+    let [
+        aaaaaaaaaaaaaaaaaaaaaaaaaa,
+        bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb,
+        cccccccccccccccccccccccccc,
+        ddddddddddddddddddddddddd,
+    ] = panic!();
+}

tests/target/style_edition/default.rs

@@ -0,0 +1,10 @@
+fn build_sorted_static_get_entry_names(
+    mut entries: Vec<(u8, &'static str)>,
+) -> (impl Fn(
+    AlphabeticalTraversal,
+    Box<dyn dirents_sink::Sink<AlphabeticalTraversal>>,
+) -> BoxFuture<'static, Result<Box<dyn dirents_sink::Sealed>, Status>>
+        + Send
+        + Sync
+        + 'static) {
+}

tests/target/style_edition/follows_edition.rs

@@ -0,0 +1,14 @@
+// rustfmt-edition: 2024
+
+fn build_sorted_static_get_entry_names(
+    mut entries: Vec<(u8, &'static str)>,
+) -> (
+    impl Fn(
+        AlphabeticalTraversal,
+        Box<dyn dirents_sink::Sink<AlphabeticalTraversal>>,
+    ) -> BoxFuture<'static, Result<Box<dyn dirents_sink::Sealed>, Status>>
+    + Send
+    + Sync
+    + 'static
+) {
+}

tests/target/style_edition/overrides_edition_when_set.rs

@@ -0,0 +1,14 @@
+// rustfmt-edition: 2018
+// rustfmt-style_edition: 2024
+fn build_sorted_static_get_entry_names(
+    mut entries: Vec<(u8, &'static str)>,
+) -> (
+    impl Fn(
+        AlphabeticalTraversal,
+        Box<dyn dirents_sink::Sink<AlphabeticalTraversal>>,
+    ) -> BoxFuture<'static, Result<Box<dyn dirents_sink::Sealed>, Status>>
+    + Send
+    + Sync
+    + 'static
+) {
+}