expressions in recipe dependencies not supported

[Ramon Rivas]

Hi, thanks for this awesome plugin.

I discovered if I add an expression on a recipe dependency, the plugin will flag it as an error, even though the just tool accepts it.

Example:

hello WHO='world': (echo 'Hello '+WHO)

echo MSG:
    echo '{{MSG}}'

The plugin will flag the + in the hello recipe as an error. I can execute just hello and it will be successfully executed.