[CS] CS for mod_whoisonline helper file

This is a bit CS for the mod_whoisonline helper file
Update helper.php
JRouterInstallation::parse() made compatible with the interface (Fix #5173)
Update en-GB.plg_system_debug.ini
Merge pull request #5125 from zero-24/patch-6

[CS] CS for mod_whoisonline helper file
Merge pull request #5176 from waader/patch-4

Insert missing space in hint text
[fix #5173] JRouterInstallation::build() strict standards
Correcting comments
Merge pull request #5198 from infograf768/(fix5173)

[fix #5173] JRouterInstallation::build() strict standards
Fixed typo introduced on PR #4308

The typo resulted on malformed contexts on save action events.
Merge pull request #5205 from amazeika/staging

Fixed typo introduced on PR #4308