imgui

In web version, update function void OpenShellURL(const std::string& url) to open link in a new browser tab.

Is your feature request related to a problem? Please describe.
Standard mode has the usual keystrokes for notepad, but there are more that would probably be useful.

Describe the solution you'd like
As a first step, a quick review of the common keystrokes in notepad/wordpad/work, for example might throw up some obvious ones we could add

Should be final since it will not be inherited

Originally posted by @litelawliet in adriengivry/Overload#126 (comment)

We should do a pass to ensure classes that should be final to have the final keyword