Improvement includes:
1. Remove reference to Lucene queries (this information is not necessary
for Elastic users, and can be outdated)
2. For `span_field_masking` include a node to use
"require_field_match" : false parameter for highlighters to work.
Closes#101804
`field_masking_span` is the only span query that does not begin with
`span_`. This commit deprecates the existing name and adds a new
name `span_field_masking` to better fit with the other queries.
