"auto_complete_selector": "text, meta.tag - punctuation.definition.tag.begin, source - comment - string.quoted.double.block - string.quoted.single.block - string.unquoted.heredoc",
I just add text scope into auto_complete_selector and it works. Nothing related to Emmet sorry. To be less aggressive, you may add text.html rather than text.
Emmet uses ! and then tab.
