Enum describing under which mode spell correction should
occur.
Values:
MODE_UNSPECIFIED (0):
Unspecified spell correction mode. In this case, server
behavior defaults to
Mode.AUTO.
SUGGESTION_ONLY (1):
Search API will try to find a spell suggestion if there is
any and put in the
SearchResponse.corrected_query.
The spell suggestion will not be used as the search query.
AUTO (2):
Automatic spell correction built by the
Search API. Search will be based on the
corrected query if found.