Both modifier_enchantress_enchant and modifier_enchantress_enchant_slow are in the ModifierNames list. However, enchant is always missing from CombatLogNames.
I believe this is a bug because Chen's holy_persuasion and holy_persuasion_teleport do appear in both lists, and are also properly displayed in the Combat Log.

Here's an example showing that the in game Combat Log doesn't log
Enchantress' Enchant.
MatchID: 21388632
[09:02.58] Enchantress receives Swiftness Aura buff from Centaur Khan.

Same issue with Helm of Dominator, but I'm not sure if this is expected because it is an item and not a skill. However, I still think any items or skills that put units under your control should be logged.