Add file status for API "Get a single commit from a repository" (#16205) (#25831)

#16205 To obtain a closer behavior to the api from github, the status
(added, modified, removed) of a file should be available in addition to
the filename.
See github doc :

https://docs.github.com/fr/rest/commits/commits?apiVersion=2022-11-28#get-a-commit

templates/swagger/v1_json.tmpl

@@ -16399,6 +16399,10 @@
         "filename": {
           "type": "string",
           "x-go-name": "Filename"
+        },
+        "status": {
+          "type": "string",
+          "x-go-name": "Status"
         }
       },
       "x-go-package": "code.gitea.io/gitea/modules/structs"