Main function for MERGE.

Fixed a typo in the docstring for SEARCH.

the docstrings on those definitions.

by "not a sequence" to allow for other sequences than vectors
and lists.

Untabified the code, which generated "false" diff lines.

Supplied embryonic docstring for SEARCH.

Supplied docstring for REDUCE.

Modified the docstring for MAP so as to make references to
any sequence of SEQUENCES more obvious.

DELETE-DUPLICATES.

Introduced an experimental paragraph "Portability notes" in the
docstring.  The idea is that the docstring otherwise reflect a real
implementation and the new paragraph warns the programmer not to rely
on implementation specific behavior.

indexes.

Introduced a description of error that always happens when bounding
indexes are invalid.

Introduced parameter descriptions for just a sequence and just a
sequence index.

Supplied docstrings for ELT and FILL.

and NSUBSTITUTE-IF-NOT.

Supplemented the wording about the test being applied in any order,
so that it also mentions that the test can be applied several times
to an element.  Added the new wording to places where it was missing.

and SUBSTITUTE-IF-NOT.

it applies to all three functions.

Added docstrings for POSITION, POSITION-IF, and POSITION-IF-NOT.

Factored out description of COUNT, COUNT-IF, and COUNT-IF-NOT.

Added a description of the PREDICATE SEQUENCE pair of arguments.

Renamed the description of satisfying the test to reflect that
it is a two-argument test.

Added descriptions of satisfying one argument tests, a positive test
and a negative test.

Added docstrings for FIND-IF, FIND-IF-NOT.

Added docstrings for COUNT-IF, COUNT-IF-NOT.

Added docstring for COUNT.