[COFF] Update comment to reflect link.exe behavior. NFC
[COFF] Update comment to reflect link.exe behavior. NFC

In my experimentation with link.exe from both VS 2015 and 2017, it
always produces images with truncated section names. Update the comment
accordingly.

Differential Revision: https://reviews.llvm.org/D42603

git-svn-id: f6089bf0e6284f307027cef4f64114ee9ebb0424@323598 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lld,llvm-mirror/lld