Feature request: Add "children" and "parent" to list of reserved keywords

[kaidesu]

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

children and parent are common keys added to collections that support parent/child relationships. These should be added to our reserved keyword ruleset.

Additional context

This cropped up when creating a navigation menu with an assigned fieldset that had a "children" field created. Once it was set, the control panel would throw a 500 error due to the fieldset children field taking precedence.

Feature request checklist

• This is a single feature (i.e. not a re-write of the entire CMS)
• The title starts with "Feature request: " and is followed by a clear feature name (Ex: Feature request: add konami code to control panel)
• I have searched for existing issues and to the best of my knowledge this is not a duplicate

[skrolikowski]

The NotAReservedKeyword rule was created for the Matrix modules that are required to generate a table (we may need to change the name).

However this request is for different issue (e.g. conflicting field names with user-defined variable names 'parent' & 'children'). An alternative suggestion would be to namespace these values like so:

$resource['related']   = [
    'parent' => new NodeResource($this->parent),
    'children' => NodeResource::collection($this->children)
];