it seems that terraform-mode, while it DOES provide
terraform-indent-level, that doesn't seem to be what actually sets the
indent level currently? possibly a bug in terraform-mode, but setting
hcl-indent-level (since hcl-mode is a dependency of terraform-mode ...)
fixes this for now, so just set them both.
- switch away from using tab to trigger completion. i find it annoying
when & how tab is "overloaded" with completion and indentation.
using ctrl+space for completion feels a bit more normal to me anyway.
- turn on auto completion pop-up triggering