RFC 43: Clarify single line per sentence specification

The markdown line length check is disabled to facilitate having a single sentence per line, making diffs easier to review and avoiding text rewrapping when changes occur in a hunk.

During implementation of this RFC we figured out that the initial intention of disabling the line length was not written down explicitly. Fix this by putting the intention and expectation into the specification section of the RFC.

Signed-off-by: Levente Polyak anthraxx@archlinux.org