Output result of apropos searching into buffer `*Apropos*'.
The value of `apropos-accumulator' is the list of items to output.
Each element should have the format
(SYMBOL SCORE FN-DOC VAR-DOC [PLIST-DOC WIDGET-DOC FACE-DOC GROUP-DOC]).
The return value is the list that was in `apropos-accumulator', sorted
alphabetically by symbol name; but this function also sets
`apropos-accumulator' to nil before returning.
If SPACING is non-nil, it should be a string; separate items with that string.
If non-nil TEXT is a string that will be printed as a heading.