Docs: add branch instructions to pull-request template.

* References #216
* Also, s/pull request/pull-request/g

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,14 +1,16 @@
-**By submitting this pull request, I confirm the following:**
+**By submitting this pull-request, I confirm the following:**
 
 - I have read and understood the [contributor guide](https://github.com/monero-project/kovri/blob/master/doc/CONTRIBUTING.md).
-- I have checked that another pull request for this purpose does not exist.
+- I have checked that another pull-request for this purpose does not exist.
 - I have considered and confirmed that this submission will be valuable to others.
-- I accept that this submission may not be used and that this pull request may be closed by the will of the maintainer.
+- I accept that this submission may not be used and that this pull-request may be closed by the will of the maintainer.
 - I give this submission freely under the BSD 3-clause license.
+- I am not basing this pull-request on branch ```master```
+- I am sending this pull-request to branch ```development```
 
 *Place an X inside the bracket (or click the box in preview) to confirm*
 - [ ] I confirm.
 
 ---
 
-*Enter your pull request summary here*
+*Enter your pull-request summary here*