Update github issue template.

Use html comments for section instructions that shouldn't be visible in
the completed form.

Signed-off-by: Rafael Kitover <rkitover@gmail.com>

.github/ISSUE_TEMPLATE.md

@@ -1,4 +1,4 @@
-### Please fill out this form:
+<!--- Please fill out this form and delete any sections you are not using. -->
 
 ### Expected behavior
 
@@ -6,13 +6,14 @@
 
 ### Steps to reproduce the behavior
 
-### Crash bugs
+<!--- Crash bugs
 
 If this is a crash bug, and you have the time and inclination, please provide a
 symblic backtrace.
 
 Instructions for doing so are
 [here](https://github.com/visualboyadvance-m/visualboyadvance-m/blob/master/README.md#reporting-crash-bugs).
+-->
 
 ### ROM details
 
@@ -38,7 +39,7 @@ If using Linux, specify if using xorg or Wayland:
 
 Version of code (pre-built binary version, or commit ref, or just "master"):
 
-### Hardware details:
+<!--- Hardware details:
 
 If your joystick or gamepad isn't working in Linux, please try to troubleshoot
 using the information on this page:
@@ -47,3 +48,4 @@ SDL for joystick support, any problems will generally be an issue with SDL and
 **NOT** the emulator.
 
 If relevant, the joystick you are using and the drivers you are using for it:
+-->