Adds a new page titled "Import your settings" in the "Account basics"
section to document how to import user settings from an existing Zulip
account to a new Zulip account, and which settings will be imported.
Adds a question mark (?) icon linking to this help page from the
registration form when the import settings option is available.
Adds cross-links on related articles.
Fixes: #20918.
Improves step-by-step instructions for Desktop users by directing
users to the relevant items in the left sidebar or top menu bar
without using an obscure keyboard shortcut.
Adds tip macro with instructions for toggling the app's left sidebar
via the top menu bar.
Moves the proxy settings and custom certificate info into a warning
block instead of the main instructions flow given they are rarely
needed for Logging in.
Adds a Related Articles section to "Switching between organizations"
so that users can access the information for setting an organization
profile picture from there instead of an oddly placed warning block.
Also adds links to "Logging in", "Logging out", and "Deactivate your
account", and lists them in each other's Related articles sections.
Adds a macro with instructions for accessing the profile menu for
reusability in "Logging out" and "Switching between organizations".
Reorders tabs Web > Desktop > Mobile for consistency.
Fixes existing errors in the help center documentation where a
keyboard shortcut that has multiple keys is all one inline code
tag (e.g. `Ctrl + [`) instead of being separated into individual
inline code tags for each key (e.g. `Ctrl` + `[`).
This is in response to a support ticket where the user had a closed left
sidebar, had added an organization, and then couldn't figure out how to
switch organizations. They had googled and found "The desktop app makes it
easy to switch between different organizations" in our help docs, which was
not sufficiently helpful.