gp: run git fetch before git push or git pull (#490)

* gp: run `git fetch` before `git push` or `git pull`

* remove useless else

---------

Co-authored-by: nash <nash@iffy.me>

modules/git/README.md

@@ -41,7 +41,9 @@ Pull, push and other related to remote repositories
 - `--override` just used to trigger a github actions event (in fact, webhooks can also be used)
 - if branch is specified, we assume it is `git fetch`
     - unless -u is specified: `git push -u`
-- finally, if no branch and above parameters are specified, `git pull` or `git push` will be executed according to the current state.
+- finally, if no branch and above parameters are specified
+    - `git fetch` to update status.
+    - `git pull` or `git push` will be executed according to the current state.
     - if both `ahead` and `behind` exist, only `pull`
 
 ### ga

modules/git/git-v2.nu

@@ -122,6 +122,7 @@ export def gp [
             git fetch $remote $branch
         }
     } else {
+        git fetch
         let s = (_git_status)
         if $s.behind > 0 {
             let r = if $rebase { [--rebase] } else { [] }
@@ -129,8 +130,6 @@ export def gp [
             git pull $r $a -v
         } else if $s.ahead > 0 {
             git push
-        } else {
-            git fetch
         }
     }
 }