Clarify & document issues using MacOS Terminal app

[neiljp]

As initially reported in #680, the MacOS Terminal app appears to not work well with the current set of application hotkeys, specifically ctrl d and those using the alt (meta) modifier.

In the FAQ, we note the existence of known issues with the Terminal app in the list of terminal emulators, but only point to issue #680. However, #680 represents a general solution to improve the user experience, ie. remapping hotkeys, in response to this platform-specific issue. In addition, there has been a recent report that at least one hotkey does work.

This issue is intended to track improving the terminal emulator FAQ entry to indicate the following (instead of pointing to #680):

• specific issues using the Terminal app
• ideas to improve the experience when using the Terminal app
• suggestions of alternative emulators for MacOS (eg. if users do not wish to change their main emulator)

The following steps are suggested:

• [ ] document the current reported situation, per the above points, using text from relevant comments in #680
• [ ] confirm and clarify the original reported problem
• [ ] clarify how much of this is related to the Terminal App, vs the MacOS system
• [ ] understand if this behavior has changed, or can/does change, over different eg.
  • [ ] releases of the Terminal app? (different default settings?)
  • [ ] MacOS releases, if they have different global shortcuts?
  • [ ] MacOS hardware (eg. intel vs ARM?)
  • [ ] keyboard layouts? (PC vs Mac? International?)
• [ ] update the documentation based on the known details

All but the first step require understanding of the original problem, and familiarity with Mac systems - possibly old and new. These should be accompanied by reliable external sources.

NOTE: For changes to the general hotkeys, particularly to optimize for a single platform, please discuss this elsewhere, such as in the #zulip-terminal stream on chat.zulip.org - such changes need to consider multiple platforms for compatibility.

[zulipbot]

Hello @zulip/server-hotkeys members, this issue was labeled with the "area: hotkeys" label, so you may want to check it out!

[Niloth-p]

Some reports from MacOS users of Zulip Terminal:

1. Progyan here, a user new to MacOS at that point of time, reports all the Meta keys worked fine with Option key, and points out that Mac users are used to using the Option key whenever they need to use Alt.
2. Sumanth here says the Option key works fine as the Meta key, by setting iTerm2 > Preferences > Profiles > Keys > Set Option key to Esc+.
3. Kelly here reports that she can use Alt + Enter as normal. Everything with Control works fine. But, Alt + ? does not work, and Cmd + ? opens up terminal's help menu, instead of a ZT menu.
4. Khushiyant opened a PR to replace Alt with Cmd. He mentions that the key mapping is correct, but it's just the instruction text that does not match him, implying that he uses the Cmd key on his keyboard for triggering the Meta key of Urwid.
5. Sushmey here clarifies that both Cmd + Fn and Option + Fn select text, but Option is more suitable than Cmd for the hotkey to select text.