Delete unnecessary template override

The README template for the 'forth' exercise was not meaningfully different than
the default template.

The only difference when regenerating the README is whitespace.

This deletes the extraneous template for the sake of simplicity.

exercises/forth/.meta/readme.go.tmpl

-# {{ .Spec.Name }}
-
-{{ .Spec.Description -}}
-{{- with .Hints }}
-{{ . }}
-{{ end }}
-{{- with .TrackInsert }}
-{{ . }}
-{{ end }}
-{{- with .Spec.Credits -}}
-## Source
-
-{{ . }}
-{{ end }}
-## Submitting Incomplete Solutions
-It's possible to submit an incomplete solution so you can see how others have completed the exercise.
-

exercises/forth/README.md

 
 
 ## Submitting Incomplete Solutions
-It's possible to submit an incomplete solution so you can see how others have completed the exercise.
 
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.