Update pull_request_template.md

.github/pull_request_template.md

@@ -4,9 +4,10 @@
 Please refer to an issue here or describe the change thoroughly in your PR.
 
 ## What is your pull request about?
-- [ ] Bug fix (non-breaking change which fixes an issue)
-- [ ] New feature (non-breaking change which adds functionality)
-- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
+- [ ] Bug fix
+- [ ] Improvement
+- [ ] New feature (adds functionality)
+- [ ] Breaking change (bug fix, feature or improvement that would cause existing functionality to not work as expected)
 - [ ] Typo fix
 - [ ] Documentation update
 - [ ] Update of other files
@@ -15,7 +16,7 @@ Please refer to an issue here or describe the change thoroughly in your PR.
 ## If it's a code change please check the boxes which are applicable
 - [ ] For the main program: My edits contain no tabs and the indentation is five spaces
 - [ ] I've read CONTRIBUTING.md and Coding_Convention.md 
-- [ ] I have tested this __fix__ against >=2 hosts and I couldn't spot a problem
+- [ ] I have tested this __fix__ or __improvement__ against >=2 hosts and I couldn't spot a problem
 - [ ] I have tested this __new feature__ against >=2 hosts which show this feature and >=2 host which does not (in order to avoid side effects) . I couldn't spot a problem
 - [ ] For the __new feature__ I have made corresponding changes to the documentation and / or to ``help()``
 - [ ] If it's a bigger change: I added myself to CREDITS.md (alphabetical order) and the change to CHANGELOG.md