Expand escaped chars in zsh completion
Expand escaped chars in zsh completion

Description fields to zsh _arguments are `eval`uated, so if we want to
get our strings through this processing verbatim, we need to escape
backticks, double-quotes, and $.
It's still almost definitely possible to slip something through this,
using some novel or exciting features of the shell, but these few
escapes should cover all current/known commands.

globus/globus-cli,globus/globus-cli