Include StackOverflow's link about MREs in issue_template.md (#2404)

Co-authored-by: Mark Hammond <mhammond@skippinet.com.au>

.github/issue_template.md

@@ -9,7 +9,7 @@ For all bugs, please provide the following information:
 ## Expected behavior and actual behavior
 
 ## Steps to reproduce the problem
-<!-- Prefer using code snippets rather than a screenshot. Please include a full minimal reproduction if possible. -->
+<!-- Prefer using code snippets rather than a screenshot. Please include a [full minimal reproduction](https://stackoverflow.com/help/minimal-reproducible-example) if possible. -->
 
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