bpo-34712: Fix style in examples in "Input and Output" (GH-9361)

bpo-34712: Fix style in examples in "Input and Output" (GH-9361)

A couple of fixes here to make this more PEP-8:

* Avoid multiple statements on one line with `;` statement separator -- this is very rare in Python and is "generally discouraged" in PEP 8 (and if used, per PEP 8 there shouldn't be a space before the `;`)
* Add output for the first "Formatted String Literals" example. (Side note: are the doctests for this being run? If so, why didn't it fail?)
* Avoid space before `!r`. I have generally not seen spaces before the `!`, and this also matches the style used in the docs here: https://docs.python.org/3/library/string.html#format-string-syntax

https://bugs.python.org/issue34712