Simplify and update pull request template

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,27 +1,19 @@
 <!--- Provide a general summary of your changes in the Title -->
 
 ## Description
-<!--- Describe your changes -->
+<!--- Use this section to describe your changes and how they're affecting the code. -->
+<!-- If your changes required testing, include information about the testing environment and the tests you ran. -->
 
-## Motivation and Context
-<!--- Why is this change required? What problem does it solve? -->
-<!--- If fixing an open issue, please link to the issue here. -->
-
-## How Has This Been Tested?
-<!--- Please describe in detail your tests. Did you add new tests? -->
-<!--- Include details of your testing environment, and the tests you ran too -->
-<!--- How were other areas of the code affected? -->
 
 ## Types of changes
 <!--- What types of changes does your code introduce? Put an `x` in all applicable boxes.: -->
-- [ ] Bug fix (non-breaking change fixing an issue)
-- [ ] New feature (non-breaking change adding functionality to spaCy)
-- [ ] Breaking change (fix or feature causing change to spaCy's existing functionality)
-- [ ] Documentation (Addition to documentation of spaCy)
+- [ ] **Bug fix** (non-breaking change fixing an issue)
+- [ ] **New feature** (non-breaking change adding functionality to spaCy)
+- [ ] **Breaking change** (fix or feature causing change to spaCy's existing functionality)
+- [ ] **Documentation** (Addition to documentation of spaCy)
 
 ## Checklist:
 <!--- Go over all the following points, and put an `x` in all applicable boxes.: -->
-- [ ] My code follows spaCy's code style.
 - [ ] My change requires a change to spaCy's documentation.
 - [ ] I have updated the documentation accordingly.
 - [ ] I have added tests to cover my changes.