Add file include support

[lekhmanrus]

It seems there are some issues with include operator support: https://pugjs.org/language/includes.html

include test

// pug code

test.pug:

p Simple test

Error:

Interesting that I'm including also file with all mixins definition, like:

include mixins

// pug code

and it works without errors.

P.S.: It worked with webpack and pug-html-loader (I had ejected webpack before). And now, after migration to Angular CLI and ng-cli-pug-loader, I have that error.

P.P.S.: Or maybe an error in pug-loader. Just noticed that I used pug-html-loader before migration.

[lekhmanrus]

It seems it is pug-loader issue: pugjs/pug-loader#105

I think this issue can be closed now. Sorry for bothering you.