Fix typos in two `libelf` manual pages.

Submitted by:	mark-jn
Ticket:		#413

git-svn-id: https://elftoolchain.svn.sourceforge.net/svnroot/elftoolchain/trunk@2884 95820547-d848-0410-985e-9ae8fe0fa350
Fix a typo in the elf.3 manual page.

git-svn-id: https://elftoolchain.svn.sourceforge.net/svnroot/elftoolchain/trunk@2885 95820547-d848-0410-985e-9ae8fe0fa350