update def syntax

[fdncred]

This updates the def syntax so that it supports these:

• def bar [...args] {}
• def bar --wrapped --env [...args] {}
• def bar --env [...args] {}
• def bar --wrapped [...args] {}
• def --wrapped --env bar [...args] {}
• def --env bar [...args] {}
• def --wrapped bar [...args] {}
• def --wrapped bar --env [...args] {}

The lsp still doesn't like it but that's a different repo.

closes #221