Update issue templates to refer to obtaining About/Exception details

[neiljp]

Description

Various information can now be easily obtained for error reporting:

• Functionality to copy information from the about popup #1521 added functionality to copy the About popup contents to the clipboard
• Copy traceback from the Exception popup #1513 added functionality to copy the Exception popup traceback to the clipboard (for threads)
• The Exception popup (for threads) already supported logging the exception to a file
• The main exception logger also logs main-thread exceptions to a different file

Given this, it would be useful to update the issue templates to suggest looking at these locations when filing an issue.

This is most importantly for bugs, but possibly also for other issues, to know when the issue was present in a given version, enabling issues to be closed more easily later if a later version should have a resolution.