[fortran,doc] Fix typo in doc

[FX]

I think the doc says “assumed-shape” where it means “assumed-rank”. Is that OK?

FX

-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: doc_patch.txt
URL: <http://gcc.gnu.org/pipermail/fortran/attachments/20131105/0829062c/attachment.txt>
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: doc_ChangeLog.txt
URL: <http://gcc.gnu.org/pipermail/fortran/attachments/20131105/0829062c/attachment-0001.txt>