Clarify selection process of new board members

The most important part of this MR is to clarify that we select board members so that the size of the board at the end of April 1 is no more than 14.

This changes our board selection process and thus requires a 2/3 vote. As this is an MR, however, we follow the rules for an MR vote (at the end of https://gitlab.haskell.org/hf/meta/-/blob/main/board.md), meaning that anyone who does not participate in the discussion, at all, abstains, meaning quorum is guaranteed.

The deadline for this vote is in two weeks, May 2.

board.md

@@ -306,12 +306,19 @@ to email the Secretary directly and thus keep their preferences more private.
 Because the votes can contain explanations, some Board members may choose to
 update their votes. This is allowed up until April 1; only the final vote counts.
 
-If the result of the election would lead to a Board of greater than 14, only
+If the result of the election would lead to a Board of greater than 14 (as
+counted at the end of April 1), only
 enough applicants are selected to bring the total size of the Board to 14.
 (This effectively moves "That's it" up in the rankings.) In the event that the
 size-14 cutoff falls in the middle of a tie, the tied applicants are not
 appointed. (This keeps the Board at a maximum size of 14.)
 
+Once candidates are selected, they are contacted by the Chair and invited to
+join the Board. If any selected candidate does not accept this invitation,
+then the next candidate further down in the ranking (up to the original location of
+"That's it") is invited, continuing until either "That's it" is reached or a size
+of 14 is reached.
+
 For example, suppose Soomin Kim, Chris Young, and Jens Pedersen are applying.
 One ranking might be