fix: inputs/.TNRS/schema.sql: added back index on Name_submitted, which is needed for tnrs_input_name to work properly (now that there is no automatic index created by a unique constraint)

fix: inputs/.TNRS/schema.sql: tnrs: removed unique constraint on Name_submitted, Name_matched because there can be more than one match with the same Name_matched (but different accepted names, etc.)

fix: inputs/.TNRS/schema.sql: tnrs.tnrs__valid_match index: made it non-unique to allow multiple matches per name, as is needed to implement #917

bugfix: inputs/.TNRS/schema.sql: tnrs__match_num__fill(): only fill if not set, to support case where tnrs is being restored from a .sql file (where match_num is already set)

inputs/.TNRS/schema.sql: tnrs: documented runtime to add a constraint (3 min)

inputs/.TNRS/schema.sql: unique constraint on Name_submitted: added Name_matched to allow multiple matches per name, as is needed to implement #917

inputs/.TNRS/schema.sql: tnrs: documented how to populate a new column

inputs/.TNRS/schema.sql: tnrs: pkey: use match_num instead of Name_number to allow multiple matches per name, as is needed to implement #917

inputs/.TNRS/schema.sql: tnrs.match_num: made it NOT NULL now that it's populated

inputs/.TNRS/schema.sql: tnrs: populate match_num