sql: quote a bare map identifier so option values round-trip

[def-]

parse_option_value accepts a MAP[k => v] literal, and that grammar commits to the map form on the MAP keyword alone and then demands [. Expression position dispatches on a two-token lookahead (MAP followed by [ or () and otherwise falls through to an identifier, but the option-value grammar has no such fallback. So an option value named map printed bare, which both AstDisplay and the pretty printer did, fails to reparse:

CREATE SINK s FROM t INTO KAFKA CONNECTION c (TOPIC = "map") FORMAT BYTES
  ENVELOPE DEBEZIUM

printed TOPIC = map, and reparsing that raised "Expected left square bracket, found right parenthesis". Every generic option value is affected, a materialized view's PARTITION BY among them.

Add MAP to Ident::can_be_printed_bare's quoting set, next to LIST, which is there for the analogous list[1] re-lex. The change is display-only: nothing that parsed before stops parsing, identifiers named map just print quoted. The comment claiming MAP was safe because MAP[...] requires => only considered expression position, and is corrected.

Found by the cargo-fuzz sql_roundtrip target. Adds a regression test beside the LIST one. The keyword-quoting fixtures in tests/testdata/select, pretty.slt and quote_ident.slt now show "map", which is what quote_ident already returned for list and array.