Support tokenizing `^` and `$` anchors

* src/paca.mjs
  (ANCHOR_FNS): Add simple handlers for ^ and $ anchors, that only look
    for the position of the character in the pattern as validation
    during tokenization.
  (isAnchor): Add simple boolean function to identify anchor characters.
  (tokenizeRegexStep): Include check if character `isAnchor()`, and call
    the appropriate `ANCHOR_FNS[char]` when true.
* tests/paca.mjs
  (test_ANCHOR_FNS): Add test with 4 cases - 2 for success and 2 for
    errors for ^ and $.
  (test_isAnchor): Add obligatory simple test cases.
  (test_tokenizeRegexStep): Include test case for tokenizing patterns
    with character class.

0 files changed, 0 insertions, 0 deletions