Non nil means apropos commands will search more extensively.
This may be slower. This option affects the following commands:
`apropos-variable' will search all variables, not just user variables.
`apropos-command' will also search non-interactive functions.
`apropos' will search all symbols, not just functions, variables, faces,
and those with property lists.
`apropos-value' will also search in property lists and functions.
`apropos-documentation' will search all documentation strings, not just
those in the etc/DOC documentation file.
This option only controls the default behavior. Each of the above
commands also has an optional argument to request a more extensive search.
Additionally, this option makes the function `apropos-library' include key-binding information in its output.