DOC: Fixes Intelligent indexing example (#11973)

docs/source/literal_types.rst

@@ -186,13 +186,13 @@ corresponding to some particular index, we can use Literal types like so:
 
  # But what if we want the index to be a variable? Normally mypy won't
  # know exactly what the index is and so will return a less precise type:
- int_index = 1
+ int_index = 0
  reveal_type(tup[int_index]) # Revealed type is "Union[str, float]"
 
  # But if we use either Literal types or a Final int, we can gain back
  # the precision we originally had:
- lit_index: Literal[1] = 1
- fin_index: Final = 1
+ lit_index: Literal[0] = 0
+ fin_index: Final = 0
  reveal_type(tup[lit_index]) # Revealed type is "str"
  reveal_type(tup[fin_index]) # Revealed type is "str"