Simplify markdown for PR template

Author: Pierstoval

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,10 +1,10 @@
 | Q             | A
 | ------------- | ---
-| Bug fix?      | [yes|no]
-| New feature?  | [yes|no]
-| BC breaks?    | [yes|no]
-| Deprecations? | [yes|no]
-| Tests pass?   | [yes|no]
-| Fixed tickets | [comma-separated list of tickets fixed by the PR, if any]
+| Bug fix?      | yes/no
+| New feature?  | yes/no
+| BC breaks?    | yes/no
+| Deprecations? | yes/no
+| Tests pass?   | yes/no
+| Fixed tickets | comma-separated list of tickets fixed by the PR, if any
 | License       | MIT
-| Doc PR        | [reference to the documentation PR, if any]
+| Doc PR        | reference to the documentation PR, if any