[LLD][ELF] - Linkerscript: report location for the "unclosed comment in a linker script" error.

Currently we print "error: unclosed comment in a linker script", which doesn't
provide information about the real error location.

Fixes https://bugs.llvm.org/show_bug.cgi?id=46793.

Differential revision: https://reviews.llvm.org/D84300