Address review

Author: sobolevn

Grammar/python.gram

@@ -1484,7 +1484,7 @@ invalid_case_block:
 invalid_case_pattern:
     | "case" a=expression guard? ':' block {
         RAISE_SYNTAX_ERROR_KNOWN_LOCATION(
-            a, "cannot use case statement with %s", _PyPegen_get_expr_name(a)) }
+            a, "cannot use %s as case pattern", _PyPegen_get_expr_name(a)) }
 invalid_as_pattern:
     | or_pattern 'as' a="_" { RAISE_SYNTAX_ERROR_KNOWN_LOCATION(a, "cannot use '_' as a target") }
     | or_pattern 'as' a=expression {

Lib/test/test_syntax.py

@@ -374,38 +374,38 @@
 ...     case {**rest, "key": value}:
 ...        ...
 Traceback (most recent call last):
-SyntaxError: cannot use case statement with dict literal
+SyntaxError: cannot use dict literal as case pattern
 
 >>> match ...:
 ...     case {**_}:
 ...        ...
 Traceback (most recent call last):
-SyntaxError: cannot use case statement with dict literal
+SyntaxError: cannot use dict literal as case pattern
 
 >>> match ...:
 ...    case ...: ...
 Traceback (most recent call last):
-SyntaxError: cannot use case statement with ellipsis
+SyntaxError: cannot use ellipsis as case pattern
 
 >>> match ...:
 ...    case 1 // 2: ...
 Traceback (most recent call last):
-SyntaxError: cannot use case statement with expression
+SyntaxError: cannot use expression as case pattern
 
 >>> match ...:
 ...    case {1, 2, 3}: ...
 Traceback (most recent call last):
-SyntaxError: cannot use case statement with set display
+SyntaxError: cannot use set display as case pattern
 
 >>> match ...:
 ...    case a[0]: ...
 Traceback (most recent call last):
-SyntaxError: cannot use case statement with subscript
+SyntaxError: cannot use subscript as case pattern
 
 >>> match ...:
 ...    case a[0].method(): ...
 Traceback (most recent call last):
-SyntaxError: cannot use case statement with function call
+SyntaxError: cannot use function call as case pattern
 
 # But prefixes of soft keywords should
 # still raise specialized errors