Add hook to run after refreshing the error list [#303]
Restructure sections in the usage document

Add separate sections for error list and error messages
Fix layout
[Fix #487] Do not recenter after error list navigation

Preserve the position if the user is inside the error list
Properly pass package names to errcheck

Work around https://github.com/kisielk/errcheck/issues/45
Fix comment

[ci skip]
Fix indentation
Improve docstring

[ci skip]
[Fix #492] Do not needlessly recenter the error list

Only recenter if there are really some errors to move into the visible
part of the window.