Decides whether a sidebar nav entry should render in its "active" state.
The Library entry is treated as active when the location is exactly
/library AND when the location is the root /, since the root path
redirects to /library and the sidebar should reflect the destination.
Parameters
currentPathname: string
useLocation().pathname from react-router. The
live URL the user is on.
navItemPath: string
The path declared on the nav item being rendered.
Returns boolean
true when the nav item should highlight, false otherwise.
Decides whether a sidebar nav entry should render in its "active" state.
The Library entry is treated as active when the location is exactly
/libraryAND when the location is the root/, since the root path redirects to/libraryand the sidebar should reflect the destination.