specl: fix premature fail fast for failing expect() after pending().

* specs/specl_spec.yaml (when failing fast): Specify behaviour of
--fail-fast (and -1) options.
* lib/specl/runner.lua (run_examples): Only stop when a failing
expect () does not follow a call to pending().
* NEWS (Bug fixes): Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
doc: remove trailing whitespace.

* doc/specl.md: Remove trailing whitespace.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>