FIX: Make shortcut 'c' global for creating a topic

https://meta.discourse.org/t/keyboard-shortcut-c-create-a-new-topic-does-not-work-globally/18975
Call open directly to avoid deprecation warning
Merge pull request #2912 from cpradio/pr-make-create-topic-global

FIX: Make shortcut 'c' global for creating a topic