Added checkboxes to acceptance criteria

Author: jackdomleo7

.github/ISSUE_TEMPLATE/a11y-feature-request.md

@@ -25,8 +25,8 @@ labels: a11y-feature
 <!--
   Provide a bullet-pointed list of acceptance criteria.
 -->
-- 
-- 
+- [ ] 
+- [ ] 
 
 
 ## Why is this a11y feature important?

.github/ISSUE_TEMPLATE/bug-report.md

@@ -35,8 +35,8 @@ Checka11y.css version:
 <!--
   Provide a bullet-pointed list of acceptance criteria.
 -->
-- 
-- 
+- [ ] 
+- [ ] 
 
 ## Why is fixing this bug important?
 <!--

.github/ISSUE_TEMPLATE/documentation.md

@@ -22,8 +22,8 @@ labels: documentation
 <!--
   Provide a bullet-pointed list of acceptance criteria.
 -->
-- 
-- 
+- [ ] 
+- [ ] 
 
 
 ## Why is this important?

.github/ISSUE_TEMPLATE/project-enhancement-idea.md

@@ -23,8 +23,8 @@ labels: project-enhancement
 <!--
   Provide a bullet-pointed list of acceptance criteria.
 -->
-- 
-- 
+- [ ] 
+- [ ] 
 
 
 ## Why is this enhancement or maintenance important?