PEP 747: fix minor typos (#4884)

Author: AshrithSagar

peps/pep-0747.rst

@@ -289,10 +289,10 @@ Explicit ``TypeForm`` Evaluation
 Type checkers should validate that this argument is a valid type expression::
 
    x1 = TypeForm(str | None)
-   reveal_type(v1)  # Revealed type is "TypeForm[str | None]"
+   reveal_type(x1)  # Revealed type is "TypeForm[str | None]"
 
    x2 = TypeForm('list[int]')
-   revealed_type(v2)  # Revealed type is "TypeForm[list[int]]"
+   reveal_type(x2)  # Revealed type is "TypeForm[list[int]]"
 
    x3 = TypeForm('type(1)')  # Error: invalid type expression