Notably, the 'single-hyphen-option' and 'assign' contexts both default to the
'none' style, so before this patch, the tests would not have detected a failure
to apply those two contexts.
For other contexts, using $unused_highlight only helps detect the case where
the right highlight style (e.g., 'fg=yellow') is used as a result of applying
the wrong context — which should be a theoretical failure mode.
This is part of zsh-users/zsh-syntax-highlighting#198.
Fixeszsh-users/zsh-syntax-highlighting#195.
The one revision made on master between this branch's creation and merge
already uses correct offsets.
* danielsh/i195-tests-offbyone-v1:
New test for dollar-double-quoted-argument.
test harness: Fix off-by-one discrepancy between observed and expected.
* Don't override user defined styles
* Better modularisation of highlighters
* Allow to define which highlighters are activated
* Allow to define the order in which they are defined
* Minor performance optimizations
* Fixed some variables leak
* Improve documentation
* Brackets highlighter: use ZSH_HIGHLIGHT_STYLES instead of a specific array
