Port `examples`, `interactions`, etc., to use the new `examples`
form of `scribble/examples`. The main intended effect is to ensure
that errors are produced by examples only as specifically
indicated.
1st is a small grammatical mistake
2nd is in a section about ->* yet mistakenly -> is referred to
3rd is about recontract-out yet contract-out is mentioned instead
4th clarifies return value for value-contract
5th replaces free-identifier? with free-identifier=?
If module M in package P imports module N from package Q,
and if N has a `lazy-require` for a module in R that is
triggered during the compilation of M, then P doesn't really
depend on R; P depends on Q, and Q depends on R, and P
shoudn't necessarily know anything about Q. At the same time,
a change to the file in R means that M must be recompiled.
So, continue to track the compilation dependency, but mark
it as "indirect" so that the package-dependency checker can
ignore the dependency.
