Update permissions UI documentation
Update permissions UI documentation

This commit adds minor clarifications to manage_grades and
view_all_grades based on bug fixes mentioned in the ticket.
Also removes /*eslint-disable*/ previously part of the file
and cleans up extra spaces within the code.

Since permissions are complex this commit also includes
other additions/removals that clarify changes that affect
other permissions (the additional considerations section).
We also clarified which permissions are not available at
the subaccount level.

Also modified this file to reflect permissions update from
Users-32, which affects courses - view usage reports and
grades - view all grades permissions.

Test plan:
- Jenkins passes

flag=none

CLOSES: USERS-158
REFS: USERS-32

Change-Id: Iee983c254a92f305d7a95de960d8640ace1884af
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/218871
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Tested-by: Jenkins
QA-Review: Landon Gilbert-Bland <60d9ff23682c863d36b48b4c32c5ce5f434d29c0@instructure.com>
Product-Review: Erin Hallmark <2a4b17b11682b229726079a631360cf016a43450@instructure.com>
Reviewed-by: Landon Gilbert-Bland <60d9ff23682c863d36b48b4c32c5ce5f434d29c0@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms