issue_template/bug_report: fix indentation (#2725)

and other trailing spaces

.github/ISSUE_TEMPLATE/bug_report.md

@@ -27,7 +27,7 @@ Thank you for taking the time to report a bug with the Gluon project.
 ### Bug report
 
 **What is the problem?**
-<!-- 
+<!--
 - What is not working as expected?
 - How is it misbehaving?
 - When did the problem first start showing up?
@@ -43,7 +43,7 @@ Thank you for taking the time to report a bug with the Gluon project.
 -->
 
 **Gluon Version:**
-<!-- 
+<!--
 Please provide a usable Git reference before applying custom patches:
 
 By using a Git reference:
@@ -58,9 +58,9 @@ Or the URL to the relevant Gluon commit
 <!--
 Please provide the URL to your site configuration repository and the
 explicit commit used to build the firmware experiencing the problem.
- 
+
 Additionally excerpts of problem-related configuration parts are 
-often helpful. 
+often helpful.
 -->
 
 **Custom patches:**