Investigate / test tfenv usage or other script like executable wrappers

This is mostly relevant to the LS, but something we should investigate.

## Known wrappers

See https://github.com/hashicorp/terraform-exec/issues/6#issuecomment-703315302 for more details.

### tfenv

`terraform` on path is now a shell script: yes
Terraform version may depend on working directory: yes

### terraform-switcher

`terraform` on path is now a shell script: no
Terraform version may depend on working directory: yes

### homebrew-terraforms

`terraform` on path is now a shell script: no
Terraform version may depend on working directory: no

### asdf

`terraform` on path is now a shell script: unknown
Terraform version may depend on working directory: unknown