Update issue templates

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,6 +1,7 @@
 ---
 name: Bug report
-about: If you've found something that does not work, please report it to help improve grocy
+about: If you've found something that does not work, please report it to help improve
+  grocy
 title: 'Bug: '
 labels: bug, ui-bug
 assignees: ''
@@ -8,3 +9,5 @@ assignees: ''
 ---
 
 Please describe the bug as detailed as possible, provide the steps how to reproduce it and maybe attach screenshots where useful.
+
+Please also check if your bug was maybe already fixed by searching closed issues here or by trying to reproduce your problem on the [pre-release demo](https://demo-prerelease.grocy.info/) (use a *private demo instance* if you want to make your example persistent).

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,6 +1,7 @@
 ---
 name: Feature request
-about: Ideas for improvements or new things which you would find useful are always welcome
+about: Ideas for improvements or new things which you would find useful are always
+  welcome
 title: 'Feature request: '
 labels: enhancement
 assignees: ''