Regression: `describe table;` is now invalid, wasn't previously

[samuelcolvin]

While working on apache/datafusion#12014 I noticed that

describe table;

Is now invalid SQL, presumably table is now a keyword or similar now?

Error:

ParserError("Expected: identifier, found: ; at Line: 1, Column: 15"

Simple failing test:

#[test]
fn test_describe_table() {
    Parser::parse_sql(&GenericDialect {}, "describe table;").unwrap();
}

[alamb]

Thank you @samuelcolvin -- I will fix this

[alamb]

(note this code has not been released yet so this does not affect 0.49.0 or earier and we plan to fix it prior to releasing 0.50.0)

[alamb]

I think this came in via #1351

[alamb]

Proposed fix: #1386