cli/patch: Spawn git for diffs directly

Spawning `rad diff` works, but prints a deprecation notice, because
`rad diff` itself is deprecated. `rad patch diff` however is not
deprecated and should just take a shortcut.

CHANGELOG.md

@@ -12,6 +12,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - The Git remote helper `git-remote-rad` now supports the options
   `pushcert [if-asked|false]`. This means it will not refuse operation
   anymore if called via `git push --signed=[if-asked|false]`.
+- `rad patch diff` does not print a deprecation notice about `rad diff`
+  being deprecated anymore. Instead, `rad patch diff` executes `git diff`
+  directly (which is what `rad diff` does anyway).
 
 ## 1.10.1 - 2026-08-12
 

crates/radicle-cli/src/commands/patch/diff.rs

@@ -25,7 +25,7 @@ pub fn run(
     };
     let (from, to) = revision.range();
 
-    process::Command::new("rad")
+    process::Command::new("git")
         .current_dir(stored.path())
         .args(["diff", from.to_string().as_str(), to.to_string().as_str()])
         .stdout(process::Stdio::inherit())