git-pull-request: add page (#10993)

* git-pull-request: add page

---------

Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>
Co-authored-by: Lena <126529524+acuteenvy@users.noreply.github.com>

pages/common/git-pull-request.md

@@ -0,0 +1,9 @@
+# git pull-request
+
+> Create a pull request for a project on GitHub.
+> Part of `git-extras`.
+> More information: <https://github.com/tj/git-extras/blob/master/Commands.md#git-pull-request>.
+
+- Create a pull request for a project on GitHub:
+
+`git pull-request {{target_branch}}`