style: apply nightly rustfmt import grouping across the workspace

rustfmt.toml sets group_imports, imports_granularity and imports_layout,
which are nightly-only; agents formatted with stable rustfmt, which
ignored them. This is a formatting-only pass with `cargo +nightly fmt`.

Test Plan:
- cargo clippy --workspace --all-targets -- -D warnings
- cargo test --workspace

crates/ghostty-build-data/src/sublime.rs

@@ -1,7 +1,9 @@
 //! Sublime syntax (also used by `bat`) (port of `extra/sublime.zig`).
 
-use crate::chunks_sublime::{C0, C1};
-use crate::config_fields;
+use crate::{
+    chunks_sublime::{C0, C1},
+    config_fields,
+};
 
 #[must_use]
 pub fn syntax() -> String {