git_tools: add more detail when commit fails

Co-Authored-By: sketch <hello@sketch.dev>
Change-ID: sae1162580ef7ab85k
diff --git a/git_tools/git_tools.go b/git_tools/git_tools.go
index fff381d..eb91ae4 100644
--- a/git_tools/git_tools.go
+++ b/git_tools/git_tools.go
@@ -451,8 +451,8 @@
 	}
 	cmd.Dir = repoDir
 
-	if err := cmd.Run(); err != nil {
-		return fmt.Errorf("error committing changes: %w", err)
+	if output, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("error committing changes: %w - git output: %s", err, string(output))
 	}
 
 	return nil