Throw ESIA if required field 'patterns' is not present in filter config.

If 'pattern_capture' tokenfilter is create / mapped without a 'patterns'
settings we now throw an exception since this is a misconfiguration and
likely due to the similar settings on related token filters.

Closes #3808
Add more anchor links to documentation

Related to #3679
Uniquify anchor links to fix asciidoc/docbook generation