refactor(cubesql): Fix manual_is_ascii_check warning

Author: mcheshkov

rust/cubesql/cubesql/Cargo.toml

@@ -105,7 +105,6 @@ len_without_is_empty = "allow"
 len_zero = "allow"
 let_and_return = "allow"
 manual_flatten = "allow"
-manual_is_ascii_check = "allow"
 manual_map = "allow"
 manual_range_contains = "allow"
 manual_strip = "allow"

rust/cubesql/cubesql/src/compile/parser.rs

@@ -23,16 +23,16 @@ impl Dialect for MySqlDialectWithBackTicks {
         // See https://dev.mysql.com/doc/refman/8.0/en/identifiers.html.
         // We don't yet support identifiers beginning with numbers, as that
         // makes it hard to distinguish numeric literals.
-        ('a'..='z').contains(&ch)
-            || ('A'..='Z').contains(&ch)
+        ch.is_ascii_lowercase()
+            || ch.is_ascii_uppercase()
             || ch == '_'
             || ch == '$'
             || ch == '@'
             || ('\u{0080}'..='\u{ffff}').contains(&ch)
     }
 
     fn is_identifier_part(&self, ch: char) -> bool {
-        self.is_identifier_start(ch) || ('0'..='9').contains(&ch)
+        self.is_identifier_start(ch) || ch.is_ascii_digit()
     }
 }