Update issue templates

.github/ISSUE_TEMPLATE/bug_report.md

+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+If you think there is a bug in PDFsharp then please use the IssueSubmissionTemplate to make the issue replicable.  
+https://docs.pdfsharp.net/General/IssueReporting.html
+
+Thanks.
+
+# Resources
+
+The official project web site:  
+https://docs.pdfsharp.net/
+
+The official peer-to-peer support forum:  
+http://forum.pdfsharp.net/
+
+# Reporting an Issue Here
+## Expected Behavior
+
+## Actual Behavior
+
+## Steps to Reproduce the Behavior
+We strongly recommend using the IssueSubmissionTemplate to make sure we can replicate the issue.  
+https://docs.pdfsharp.net/General/IssueReporting.html