Code review comment for lp:~thumper/juju-core/testing-docs

Minor fixes

https://codereview.appspot.com/96110043/diff/1/doc/how-to-write-tests.txt
File doc/how-to-write-tests.txt (right):

https://codereview.appspot.com/96110043/diff/1/doc/how-to-write-tests.txt#newcode165
doc/how-to-write-tests.txt:165: To create your new test suite composing
one of the following, you can
Clearer as:

To create a new suite composed of one or more of the suites above, you
can do something like:

https://codereview.appspot.com/96110043/diff/1/doc/how-to-write-tests.txt#newcode207
doc/how-to-write-tests.txt:207: in the compisition tree, there are a few
very helpful functions.
composition

https://codereview.appspot.com/96110043/diff/1/doc/how-to-write-tests.txt#newcode223
doc/how-to-write-tests.txt:223: PatchValue works with any matching type.
This includes function variables.
Is it possible to patch methods? I'm guessing it isn't, but if it is
could you add an example here?

https://codereview.appspot.com/96110043/