Merge branch 'master' into 'master'

Update start-using-git.md to reflect that merges to master can be made from either the master or the named branch.

## What does this MR do?

The documentation is incorrect in stating that you need to be in the named branch in order to merge to master.  You can be in master and merge the named branch, too.

## Are there points in the code the reviewer needs to double check?

Yes

## Why was this MR needed?

This MR is needed to correct an inaccuracy in the documentation.

## What are the relevant issue numbers?

N/A

## Screenshots (if relevant)

N/A

## Does this MR meet the acceptance criteria?

It is only a documentation change, so mostly this is not applicable.

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5404

doc/gitlab-basics/start-using-git.md

@@ -120,3 +120,11 @@ You need to be in the created branch.
 git checkout NAME-OF-BRANCH
 git merge master
 ```
+
+### Merge master branch with created branch
+You need to be in the master branch.
+```
+git checkout master
+git merge NAME-OF-BRANCH
+```
+