en to en_GB translation catalogue (4 entries)

note: i18n: ectx: property (windowTitle), widget (QWidget, OxygenStyleConfig)
en: Dialog
en_GB: Dialogue

note: i18n: ectx: property (text), widget (QRadioButton, _menuHighlightDark)
en: Use dar&k color
en_GB: Use dar&k colour

note: i18n: ectx: property (text), widget (QRadioButton, _menuHighlightStrong)
en: &Use selection color (plain)
en_GB: &Use selection colour (plain)

note: i18n: ectx: property (text), widget (QRadioButton, _menuHighlightSubtle)
en: Use selec&tion color (subtle)
en_GB: Use selec&tion colour (subtle)
