[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

llvm-svn: 323598

lld/COFF/Writer.cpp

@@ -581,9 +581,8 @@ void Writer::createSymbolAndStringTable() {
       continue;
     // If a section isn't discardable (i.e. will be mapped at runtime),
     // prefer a truncated section name over a long section name in
-    // the string table that is unavailable at runtime. This is different from
-    // what link.exe does, but finding ".eh_fram" instead of "/4" is useful
-    // to libunwind.
+    // the string table that is unavailable at runtime. Note that link.exe
+    // always truncates, even for discardable sections.
     if ((Sec->getPermissions() & IMAGE_SCN_MEM_DISCARDABLE) == 0)
       continue;
     Sec->setStringTableOff(addEntryToStringTable(Name));