`--fmt` should imply `-t`

[simonw]

Not sure why I didn't implement this.

[simonw]

Need to change if table: to if table or fmt: in a few places.

[simonw]

Better:

if fmt:
    table = True

[simonw]

Commands that support --fmt (via the @output_options decorator) are:

• tables
• views
• query
• memory
• search
• rows
• triggers
• indexes

[simonw]

In addition to a unit test I manually tested all of the above, e.g.

% sqlite-utils indexes global-power-plants.db sqlite_master --fmt rst
=======  ============  =======  =====  ======  ======  ======  =====
table    index_name    seqno    cid    name    desc    coll    key
=======  ============  =======  =====  ======  ======  ======  =====
=======  ============  =======  =====  ======  ======  ======  =====