update comment to fix typo and clarify

Author: maxcountryman

src/parser.rs

@@ -184,7 +184,7 @@ impl Parser {
 
     /// Parse an expression prefix
     pub fn parse_prefix(&mut self) -> Result<Expr, ParserError> {
-        // PostgreSQL allows any string literal to be prceded by a type name, indicating that the
+        // PostgreSQL allows any string literal to be preceded by a type name, indicating that the
         // string literal represents a literal of that type. Some examples:
         //
         //      DATE '2020-05-20'
@@ -198,8 +198,8 @@ impl Parser {
         //      INTERVAL '7' DAY
         //
         // Note also that naively `SELECT date` looks like a syntax error because the `date` type
-        // name is not followed by a string literal, but in fact is a valid expression that should
-        // parse as the column name "date".
+        // name is not followed by a string literal, but in fact in PostgreSQL it is a valid 
+        // expression that should parse as the column name "date".
         maybe!(self.maybe_parse(|parser| {
             match parser.parse_data_type()? {
                 DataType::Interval => parser.parse_literal_interval(),