[FEATURE] Alias slack types

[WilliamBergamin]

Description of the problem being solved

Slack-specific types (rich-text, channels, usergroups) found in Schame.slack.types are not easily discoverable. This is partly caused by them being separated from primitives (string, boolean, etc.) found in Schema.types

Alternative solutions

Aliasing Schame.slack.types to Schema.types.slack could improve discoverability of Slack-specific types (rich-text, channels, usergroups). The goal would be to make Slack-specific types "sub-types" of the Schema.types primitives (string, boolean, etc.). This would make the developers autocomplete recommend Slack-specific types in Schema.types

Requirements

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