Use #| instead of #= in why.t

The current version of why.t is actually broken; it is #| that
is supposed to attach to declarations following it, rather
than #=.  #= should attach to a preceding declaration.
Rename why.t to why-preceding.t

Declare its nature more clearly; more tests to follow
S26: Add a test for #=

Comments of the #= type document the preceding declaration
S26: Test combination of leading and trailing doc comments
Test documentation on params
Stop skipping test that now no longer segfaults
Fix attribute lookup test
Fix why-following attribute comment test
Add names to why-following tests
Fix typo in module leading/trailing comment
Don't skip attribute test for leading/trailing comments
Add trailing comment for attributes for why-both
Rename WHY tests to reflect names given in docs
Fix up integration test for 2011 advent calender post
Check leading
Check definedness of trailing properties if none are provided
Flesh out trailing WHY tests a bit
Add leading/trailing checks to why-both.t
Test WHEREFORE in leading docs
Name WHEREFORE tests