cmcmd: Clarify comment explaining vs_link_{exe,dll} output encoding

Revise the comment from commit 7e359823c9 (MSVC: Preserve linker output
encoding, 2018-08-03, v3.13.0-rc1~223^2) to more clearly explain why we
need to write output using a `cmConsoleBuf` without `SetUTF8Pipes`.
1 file changed