Remove unnecessary NRoot context bound.
Remove unnecessary NRoot context bound.

Fixes #251. Thanks adelbertc!

adampingel/spire,codeaudit/spire,kevinmeredith/spire,guersam/spire,codeaudit/spire,woparry/spire,JackSullivan/spire,adampingel/spire,JackSullivan/spire,siddhartha-gadgil/spire,AlecZorab/spire,non/spire,siddhartha-gadgil/spire,kevinmeredith/spire,tixxit/spire,AlecZorab/spire,non/spire,tixxit/spire,guersam/spire,rklaehn/spire,woparry/spire,rklaehn/spire