Validate the hint spawn fix as well as add feature tests for previously
untested hinting behaviors (fill, run, --rapid).
There is still no test for the 'userscript' target as running a
userscript from hint mode during a test does not get the same
redirection as the 'I execute the userscript ...' statement, That is,
it looks in /usr/local/share/qutebrowser/userscripts rather than
tests/integration/data/userscripts.