Controls what keyword matching behavior the search has. When keyword
matching is enabled, a keyword match returns jobs that may not match
given category filters when there are matching keywords. For
example, for the query "program manager" with KeywordMatchMode set
to KEYWORD_MATCH_ALL, a job posting with the title "software
developer," which doesn't fall into "program manager" ontology, and
"program manager" appearing in its description will be surfaced.
For queries like "cloud" that don't contain title or location
specific ontology, jobs with "cloud" keyword matches are returned
regardless of this enum's value.
if company-specific globally matched custom field/attribute string
values are needed. Enabling keyword match improves recall of
subsequent search requests.