Point out a! in manual and ??, and note context sensitive help in ??

and I screens.

git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@9268 c06c8d41-db1a-0410-9941-cceddc491573

Created by  dploog  on February 27, 2009
IISZ2GV3N6S5RTIBUMDNQXWDF7UCJYD3GX5XVAAZARWSZPOMRSXQC
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