Update PULL_REQUEST_TEMPLATE.md

Author: verhovsky

.github/PULL_REQUEST_TEMPLATE.md

@@ -2,5 +2,5 @@
 - [ ] Pull request title is prepended with `[language/lang-code]` (example `[python/fr]` or `[java/en]`)
 - [ ] Pull request touches only one file (or a set of logically related files with similar changes made)
 - [ ] Content changes are aimed at *intermediate to experienced programmers* (this is a poor format for explaining fundamental programming concepts)
-- [ ] If you've changed any part of the YAML Frontmatter, make sure it is formatted according to [CONTRIBUTING.md]([https://github.com/adambard/learnxinyminutes-docs/blob/master/CONTRIBUTING.markdown](https://github.com/adambard/learnxinyminutes-docs/blob/7069599e41111166a307cd3e1dccf29ee0b96f31/CONTRIBUTING.md)
+- [ ] If you've changed any part of the YAML Frontmatter, make sure it is formatted according to [CONTRIBUTING.md](https://github.com/adambard/learnxinyminutes-docs/blob/master/CONTRIBUTING.md)
   - [ ] Yes, I have double-checked quotes and field names!