Move omitting redacted_because into proposal and add security consideration
Move omitting redacted_because into proposal and add security consideration

Signed-off-by: Tulir Asokan <d52a095ed9643bd427acb6654f10f4a52fda6a79@maunium.net>

matrix-org/matrix-doc,matrix-org/matrix-doc,matrix-org/matrix-doc,matrix-org/matrix-doc