Add episode numbers as an option

[mattstratton]

It would be useful to be able to specify an episode number in the frontmatter of an episode, which would then be able to take a prefix from the config file to append to the title on the display, as it is done on https://www.arresteddevops.com.

For example, config.toml would have a field called episode_prefix, like "ADO", and then that would generate a title like

My Episode - ADO89

[mattstratton]

So I think code looks something like

$.Scratch.Set "episode_prefix" ""
{{ with $.Site.Params.episode_prefix }}
  {{ $.Scratch.Set "episode_prefix" "(" }}
  {{ $.Scratch.Add "episode_prefix" $.Site.Params.episode_prefix }}
  {{ $.Scratch.Add "episode_prefix" ")" }}
 {{end}}
 
{{.Title}}{{ with .Params.episode_number }}&nbps;{{ . }}{{ $.Scratch.Get "episode_prefix }}{{ end }}

Could even get tricker and add an optional field to specify what should surround the episode number (parens or square braces, etc)

[mattstratton]

I have confused myself and don't know why I was going to do the parens around it. From what I can tell in the example, it would output something like My Episode (ADO89) not My Episode - ADO98.

Also the code is bad because I already have the value of %.Site.Params.episode_prefix available in the . from the with statement :)

[mattstratton]

but I think you could do like three options, set with episode_number_style in the config, like this (these are the three options):

[params]
episode_number_style  = "parens"
episode_number_style = "brackets"
episode_number_style = "dash"

which would result in the following:
My Episode (ADO89)
My Episode [ADO89]
My Episode - ADO89

[mattstratton]

as another update so I don't forget - the episode = "" already exists in frontmatter, and is used in the feed:

          {{ with .Params.episode }}
          <itunes:episode>{{ . }}</itunes:episode>
          {{ end }}

[mattstratton]

This is connected to #67