Fix comments about IndirectBrInst in Instructions.h

Patch by yo (Chiang, Yi-Yo) <yo@skymizer.com>.
Differential Revision: https://reviews.llvm.org/D23982

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280241 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed