DOCS-1111 clarify sort operations with index

DOCS-1111 incorporate some code review feedback

DOCS-1111 clarify sort operations with index

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-1723 glossary edits - part 2

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-1758: clarify possible permissions issue.
DOCS-1757: clarifying broken sentence.
fix findAndModify: either update and remove field is mandatory