Token (& token type) machine name requirements

Background:
The description under machine name for a custom token says "A unique machine-readable name for this token. It must only contain lowercase letters, numbers, and underscores." This is properly enforced, underscores work, hyphens do not.

The description under machine name for a custom token TYPE says "A unique machine-readable name for this token. It must only contain lowercase letters, numbers, and underscores." But the if you use an underscore you get an error which says "The machine-readable name must contain only lowercase letters, numbers, and hyphens." Hyphens work, underscores do not.

Proposed solution(s)
1) Preferred: make the two consistent with the rest of drupal by using the machine name element that is included in drupal core (https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Render%21...).

Alternatives 2) make the two consistent within code so that they both allow hyphens and/or both allow underscores and make the descriptions accurate.

Alternative 3) make the descriptions accurate.