fix: Remove number matching from COLON placeholder parser (#3761)

Author: VaggelisD

sqlglot/parser.py

@@ -777,7 +777,7 @@ class Parser(metaclass=_Parser):
         TokenType.PARAMETER: lambda self: self._parse_parameter(),
         TokenType.COLON: lambda self: (
             self.expression(exp.Placeholder, this=self._prev.text)
-            if self._match(TokenType.NUMBER) or self._match_set(self.ID_VAR_TOKENS)
+            if self._match_set(self.ID_VAR_TOKENS)
             else None
         ),
     }

tests/fixtures/identity.sql

@@ -53,6 +53,7 @@ x >> 1 | 1 & 1 ^ 1
 x || y
 x[ : ]
 x[1 : ]
+x[ : 2]
 x[1 : 2]
 x[-4 : -1]
 1 - -1