grammar typo, "is mark" should be "is marked", and "it satisfies" should be "satisfy"

Existing Wording:

f any sub-element is mark as must support it must meet the must support requirements as well and it satisfies the must support requirement for the parent element.

Proposed Wording:

f any sub-element is marked as must support it must meet the must support requirements as well and satisfy the must support requirement for the parent element.

(Comment 61 - imported by: Jean Duteau)