FAQ: Update symbol rendering information.

This commit updates the FAQ regarding symbol rendering
information. It also specifies that we provide a tool that
can be used to test symbol rendering in terminal emulators.

A previous section regarding setting the terminal's encoding has
been removed, since ZT now sets the encoding itself, removing the
need for a user to do it.

docs/FAQ.md

@@ -66,6 +66,15 @@ One session of Zulip Terminal represents a connection of one user to one Zulip s
 
 Since we expect the above to be straightforward for most users and it allows the code to remain dramatically simpler, we are unlikely to support multiple Zulip servers within the same session in at least the short/medium term. However, we are certainly likely to move towards a system to make access of the different servers simpler, which should be made easier through work such as [zulip-terminal#678](https://github.com/zulip/zulip-terminal/issues/678).
 
+<<<<<<< HEAD
+=======
+## Unable to render symbols
+
+If some symbols don't render quite right on your terminal, it could likely be because of the symbols not being supported on the emulator/font.
+
+You can run `zulip-term-check-symbols` to check whether or not the symbols render properly on your terminal emulator and/or font.
+
+>>>>>>> d6d0371... FAQ: Update symbol rendering information.
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