docs: remove note about required quotes for system columns
docs: remove note about required quotes for system columns

that is no longer necessary

husky-koglhof/crate,husky-koglhof/crate,crate/crate,aslanbekirov/crate,EvilMcJerkface/crate,EvilMcJerkface/crate,sunny256/crate,aslanbekirov/crate,gmrodrigues/crate,adrpar/crate,gmrodrigues/crate,sunny256/crate,EvilMcJerkface/crate,husky-koglhof/crate,puneetjaiswal/crate,crate/crate,adrpar/crate,adrpar/crate,gmrodrigues/crate,sunny256/crate,puneetjaiswal/crate,aslanbekirov/crate,puneetjaiswal/crate,crate/crate