Don't wrap an array just to get its length.

Use .length directly, avoiding the allocation of the WrappedArray.
Remove redundant explicit returns.
Modernize legacy backquotes in comments.

Was: ``blah''
Now: `blah`
Address some Scaladocrot

 - @param tags whose name drifted from the corresponding parameter
 - Remove or complete a few stray stub comments (@param foo ...)
 - Use @tparam where appropriate.