gh-129545 Enhance error messages

Author: sharktide

Lib/test/test_syntax.py

@@ -394,12 +394,12 @@
 >>> def f(x, y=1, z):
 ...     pass
 Traceback (most recent call last):
-SyntaxError: parameter without a default follows parameter with a default
+SyntaxError: positional parameter without a default follows parameter with a default
 
 >>> def f(x, /, y=1, z):
 ...     pass
 Traceback (most recent call last):
-SyntaxError: parameter without a default follows parameter with a default
+SyntaxError: positional parameter without a default follows parameter with a default
 
 >>> def f(x, None):
 ...     pass
@@ -622,11 +622,11 @@
 
 >>> lambda a,d=3,c: None
 Traceback (most recent call last):
-SyntaxError: parameter without a default follows parameter with a default
+SyntaxError: positional parameter without a default follows parameter with a default
 
 >>> lambda a,/,d=3,c: None
 Traceback (most recent call last):
-SyntaxError: parameter without a default follows parameter with a default
+SyntaxError: positional parameter without a default follows parameter with a default
 
 >>> import ast; ast.parse('''
 ... def f(