Revise 2 points in the manual: encoding and an example

First, since the commit 52bfb856 introduces non-ASCII characters into the manual, i think it'll be better to specify the encoding. (At least my Emacs couldn't auto-detect the appropriate encoding.)

Second, I modified the example of package-inferred-system because the name of the example system was inconsistent: my-lib and lil. And then I added an example of :use-reexport for .../all-style packages.