EIP number assignment clarification

[expede]

howto-eip-presentation/index.html

Line 204 in 201b8e8

<li>Assign an EIP number</li>

howto-eip-presentation/index.html

Line 402 in 201b8e8

<li>IF agreeable, EIP editor will assign the EIP a number</li>

Minor correction: EIP numbers are assigned (by convention) to the PR number that they're opened under. The author adds the number once it is known (ie: the PR is opened), not the editor