Update delete.txt

Changed "affect" for "effect" (typo)

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-1492 remove unused files

Signed-off-by: Sam Kleinman <samk@10gen.com>
Update execution guidance to mention lack of auto-complete or friendly execution of collections with dash in addition to the already mentioned "starts with numbers" or "contains a space".

Signed-off-by: Sam Kleinman <samk@10gen.com>