Improve status command output

[marcransome]

Is your feature request related to a problem? Please describe.

The status command could be improved to provide output that better distinguishes between status descriptions and their values—potentially using text padding or alignment—as well as to provide additional detail such as the size, loaded state, and presence of any init or deinit functions.

Describe the solution you'd like

The following examples include proposed solutions for both the global status output and pond status respectively. In both cases a suitable UTF bullet point character (coloured green/red) could be used to indicate:

• overall health (i.e. functions across all ponds are syntactically valid) for the global status output (i.e. pond status)
• whether a pond is loaded or not in the case of a named pond (i.e. pond status abc)

Proposed global status output:

● pond <version-or-sha>
    Health: good (functions syntax checked)
     Ponds: 2 (0 enabled; 2 loaded)
 Functions: 1
    Loaded: /home/nobody/.config/fish/pond
            ├─• abc
            └─• xyz

Proposed output for a named pond (i.e. pond status abc):

● abc (/home/nobody/.config/fish/pond/abc)
    Loaded: loaded (fish_function_path)
   Enabled: disabled (pond_function_path)
    Syntax: good
      Init: yes
    Deinit: no
 Functions: 1
      Size: 8.0K