File -> Settings -> Editor -> Smart Keys -> Uncheck Automatically insert required attributes
However, you should use space
instead of pressing enter
to do the autocomplete as pressing enter would close the tag (unchecking not to insert closing tag didn't work for me in this case).
If using space
you can also uncheck Automatically start attribute
depending on your needs. With this checked it will add a =""
to allow to start typing in an attribute.
Edit
For using the space
key to autocomplete:
File -> Settings -> Editor -> Code Completion -> Check Insert selected variant by typing dot, space, etc.