Nudge new users towards using this style:
```lua
local config = {}
config.color_scheme = 'Batman'
return config
```
and surface how to write lua modules closer to the main section
on config files. In that lua modules section, nudge towards using
a convention similar to that of the plugin spec described in
this commit: e4ae8a844d
Add `get_foreground_process_name` to both Pane and the lua wrapper.
Add `foreground_process_name` and `current_working_dir` fields to
`PaneInformation`. In order for those to be dynamically fetched,
switch the lua conversion for `PaneInformation` to be a UserData
with field access methods. It's a little more verbose but allows
us to lazily compute these two new fields.
refs: https://github.com/wez/wezterm/discussions/1421
refs: https://github.com/wez/wezterm/issues/915
refs: https://github.com/wez/wezterm/issues/876
