docs(form): Add comma to line 319 for readability
docs(form): Add comma to line 319 for readability

Line 319 is hard to read on the first glimpse.

Currently the sentence reads:
"In Angular forms can be nested"

The sentence should read either
"In Angular, forms can be nested"
or
"Forms can be nested in angular"

I changed it to the former in this pull request.

Closes #11271

ggershoni/angular.js,ggershoni/angular.js,ggershoni/angular.js,ggershoni/angular.js