How to: Extra or missing spaces in prompt compared to Powerlevel9k
tl;dr: Add `ZLE_RPROMPT_INDENT=0` and `POWERLEVEL9K_LEGACY_ICON_SPACING=true` to `~/.zshrc` to get
the same prompt spacing as in Powerlevel9k.

When using Powerlevel10k with a Powerlevel9k config, you might get additional spaces in prompt here
and there. These come in two flavors.

#### Extra space without background on the right side of right prompt

tl;dr: Add `ZLE_RPROMPT_INDENT=0` to `~/.zshrc` to get rid of that space.

From [Zsh documentation](
  http://zsh.sourceforge.net/Doc/Release/Parameters.html#index-ZLE_005fRPROMPT_005fINDENT):

> `ZLE_RPROMPT_INDENT
`
>
> If set, used to give the indentation between the right hand side of the right prompt in the line
> editor as given by `RPS1` or `RPROMPT` and the right hand side of the screen. If not set, the
> value `1` is used.
>
> Typically this will be used to set the value to `0` so that the prompt appears flush with the
> right hand side of the screen.

Powerlevel10k respects this parameter. If you set `ZLE_RPROMPT_INDENT=1` (or leave it unset, which
is the same thing as setting it to `1`), you'll get an empty space to the right of right prompt. If
you set `ZLE_RPROMPT_INDENT=0`, your prompt will go to the edge of the terminal. This is how it
works in every theme except Powerlevel9k.

![ZLE_RPROMPT_INDENT: Powerlevel10k vs Powerlevel9k](
  https://raw.githubusercontent.com/romkatv/powerlevel10k-media/master/p9k-vs-p10k-zle-rprompt-indent.png)

Powerlevel9k issue: [powerlevel9k#1292](https://github.com/Powerlevel9k/powerlevel9k/issues/1292).
It's been fixed in the development branch of Powerlevel9k but the fix hasn't yet made it to
`master`.

Add `ZLE_RPROMPT_INDENT=0` to `~/.zshrc` to get the same spacing on the right edge of prompt as in
Powerlevel9k.

*Note:* Several versions of Zsh have bugs that get triggered when you set `ZLE_RPROMPT_INDENT=0`.
Powerlevel10k can work around these bugs when using powerline prompt style. If you notice visual
artifacts in prompt, or wrong cursor position, try removing `ZLE_RPROMPT_INDENT` from `~/.zshrc`.

#### Extra or missing spaces around icons

tl;dr: Add `POWERLEVEL9K_LEGACY_ICON_SPACING=true` to `~/.zshrc` to get the same spacing around
icons as in Powerlevel9k.

Spacing around icons in Powerlevel9k is inconsistent.

![ZLE_RPROMPT_INDENT: Powerlevel10k vs Powerlevel9k](
  https://raw.githubusercontent.com/romkatv/powerlevel10k-media/master/p9k-vs-p10k-icon-spacing.png)

This inconsistency is a constant source of annoyance, so it was fixed in Powerlevel10k. You can add
`POWERLEVEL9K_LEGACY_ICON_SPACING=true` to `~/.zshrc` to get the same spacing around icons as in
Powerlevel9k.

*Note:* It's not a good idea to define `POWERLEVEL9K_LEGACY_ICON_SPACING` when using
`p10k configure`.