Template:Nationality television episodes by decade category/doc

Creates a category of the form "nationality television episodes by decade", where nationality is a valid nationality.

e.g.
 * Category:Canadian television episodes by decade ✅
 * Category:British television episodes by decade ✅
 * Category:Australian television episodes by decade ✅

It is not for use on other categories, e.g.
 * Category:Australian television episodes ❌
 * Category:Canadian television episodes by year ❌
 * Category:2017 American television episodes ❌

Usage
No parameters needed

Errors
If the template is used on an invalid page, an error message is generated and the page is categorised in:
 * Category: (population: )

Errors include:


 * The page is not in the category namespace
 * The page's title does not take the form "nationality television episodes by decade"
 * The value of "nationality" does not correspond to a country name.  The conversion is made using GetCountryNameFromAdjective, so the problem may be a glitch in that template's lookup table