\section fish_mode_prompt fish_mode_prompt - define the appearance of the mode indicator

\subsection fish_mode_prompt-synopsis Synopsis

fish_mode_prompt will output the mode indicator for use in vi-mode.

\subsection fish_mode_prompt-description Description

The output of `fish_mode_prompt` will be displayed in the mode indicator position to the left of the regular prompt.

Multiple lines are not supported in `fish_mode_prompt`.
