refactor(bug.md): minor restructuring, improve Markdown styling

.gitlab/merge_request_templates/Bugfix.md

 # Bug fix
 
-Well, it seems that it is impossible to write software without bugs. That's why
-we are really happy that you are here. Thank you very much! Please take a moment
-to help us include the purposed bug fix by filling out the following form.
+Well, it seems that it is impossible to write software without bugs.
+That's why we are really happy that you are here.
+Thank you very much!
+Please take a moment to help us include the purposed bug fix by filling out the following form.
 
 Feel free to delete sections that doesn't suit the case you're dealing with.
 
+## Summary
+
+Apart from what is mentioned in the main ticket you are going to close with this
+MR, tell us what you have done to achieve this goal.
+
 ## Related Tickets
 
-Add all related issues and especially those to be closed. Keep in mind that every
-`bugfix` branch needs an issue that properly describes the bug beforehand. If your
-fix addresses something untracked, please open a ticket first.
+Add all related issues and especially those to be closed.
+Keep in mind that every `bugfix` branch needs an issue that properly describes the bug beforehand.
+If your fix addresses something untracked, please open a ticket first.
 
 ## Does the result of the MR comply to our "definition of done"?
 
@@ -25,10 +31,6 @@ fix addresses something untracked, please open a ticket first.
 
 ### Closes
 
-## Summary
-
-Apart from what is mentioned in the main ticket you are going to close with this
-MR, tell us what you have done to achieve this goal.
 
 ## Changelog