doc: Fix manual's link attributes example code
doc: Fix tutorial typo and remove unnecessary xfail-test
doc: Fix tutorial-ffi xfail-tests and update SHA1() to use size_t
Enable lint warnings for doc tests
Merge pull request #4563 from cpeterso/fix-doc-tests

Fix various doc tests
style fix
add clear method to TreeMap/TreeSet
add a Mutable container trait
add a container::Map trait
add a base Container trait