Fix &entities; that lacked an ending ';' character,
as reported by the following:
% cd doc/en_US.ISO8859-1
% find . -type f -name '*.sgml' |\
xargs grep '&[^[:space:];&][^[:space:];]*$' | grep -v '&$'
% find . -type f -name '*.sgml' |\
xargs grep '&[^[:space:];&][^[:space:];]*[[:space:]<]' |\ grep -v '&[[: space:]]' | grep -v '[[:space:]]&&[[:space:]]'