Rename folder to directory

Author: ehmicky

.github/pull_request_template.md

@@ -29,7 +29,7 @@ Please add a `x` inside each checkbox:
 
 - [ ] I have read the [contribution guidelines](CONTRIBUTING.md)
 - [ ] I have added tests (we are enforcing 100% test coverage).
-- [ ] I have added documentation in the `README.md`, the `docs` folder (if any)
-      and the `examples` folder (if any).
+- [ ] I have added documentation in the `README.md`, the `docs` directory (if
+      any) and the `examples` directory (if any).
 - [ ] The status checks are successful (continuous integration). Those can be seen
       below.

CONTRIBUTING.md

@@ -46,8 +46,8 @@ We enforce 100% test coverage: each line of code must be tested.
 Documentation must be added for any new feature in all of these:
 
 - the `README.md`
-- the `docs` folder (if any)
-- the `examples` folder (if any)
+- the `docs` directory (if any)
+- the `examples` directory (if any)
 
 After submitting the pull request, please make sure the Continuous Integration
 checks are passing.