PULL_REQUEST_TEMPLATE.md: use more robust links

relative links may not work if the PR is created from a branch containing slashes in it.

Author: waldyrious

.github/PULL_REQUEST_TEMPLATE.md

@@ -5,5 +5,5 @@
 - [ ] The page (if new), does not already exist in the repo.
 - [ ] The page is in the correct platform folder (`common/`, `linux/`, etc.)
 - [ ] The page has 8 or fewer examples.
-- [ ] The PR title conforms to the recommended [templates](../blob/master/CONTRIBUTING.md#commit-message).
-- [ ] The page follows the [content guidelines](../blob/master/CONTRIBUTING.md#guidelines).
+- [ ] The PR title conforms to the recommended [templates](/tldr-pages/tldr/blob/master/CONTRIBUTING.md#commit-message).
+- [ ] The page follows the [content guidelines](/tldr-pages/tldr/blob/master/CONTRIBUTING.md#guidelines).