Fixes #630.

Fixes #676.

Computing ${#array} is O(N), whereas checking 0 is O(1).

* commit 'b1f36d9c5f45b879fbd2f64195167a60d9f3cb9e':
  'main': Add a comment.
  'main': Fix the $CDPATH from the previous commit.
  'main': Add a test for a $CDPATH bug.

Uses the infrastructure added in the previous commit.

Fixes #678.

This prevents the baz pattern match from being attempted whenever the
bar pattern match was tried and failed.

No functional change.

Before this commit, the test was unable to XPass, since there is no
highlighting style called "normal".

* danielsh/tests-skip-cardinality-v1:
  tests: Minor documentation readability tweak
  Add a test for issue #641.5, using the infrastructure added in the previous commits.
  tests: Skip cardinality tests whenever any test point is expected to fail.
  tests: Make $expected_mismatch skip the cardinality check, rather than consider it an expected failure.
  tests: Include the name of the 'cardinality check' test point in the output

Fixes #692.

Before this commit, the command word was highlighted as "unknown-token"
not because alias loops are invalid, as a comment incorrectly claimed,
but because the command word «a» resolved to a «b» that was ineligible
for being expanded as an alias, and there was no function/builtin/etc.
called "b".

Add a function "b" to demonstrate that alias loops are valid.  I've also
filed issue #695 about the overloading of "unknown-token".

Fixes #501.

Fixes #616 (the original form; not the form in
test-data/alias-comment1.zsh which is now considered o be #677 (see
previous commit for details)).

Fixes a latent bug in test-data/always2.zsh.

No user-visible effect, and therefore, no changelog entry.

See https://github.com/zsh-users/zsh-syntax-highlighting/issues/677#issuecomment-599225740 for details.

(In particular, there's already another test that calls itself #616.)

Fixes #651.

Fixes the test added in the penultimate (grandparent) commit.

Used by the next commit.

- pipes (issue #651)
- semicolons
- literal newlines
  (also discussed on #651)

The «emulate» call isn't sufficient, since these lines are parsed before
it takes effect.

Fixes #689 (née #622).

See also #688 for preventing these gymnastics from being needed in the
first place.

See also https://github.com/junegunn/fzf/pull/1924 for an inter-plugin
interaction that this probably fixes.

This makes the tests more reproducable. In particular it avoids hiding
a WARN_CREATE_GLOBAL error when the dev happens to have defined that
variable in the environment (cf. next commit).

Fixes #646.

It is fixed in the next commit.

Required for the next commit.