Drop BSD-3 file copyright exception

Our Haskell-based benchmark-lsp program was BSD-3-licensed. However, the
new C++-based program is GPLv3-licensed. Reinstate the GPLv3 checks in
our check-file-copyrights tool for benchmark-lsp.

Author: strager

tools/check-file-copyrights

@@ -14,7 +14,6 @@ check_file_copyright_header() {
   local file="${1}"
   case "${file}" in
     benchmark/benchmark-lsp/corpus/*) ;;
-    benchmark/benchmark-lsp/*) check_file_copyright_header_benchmark_lsp "${file}" ;;
     dist/winget/*.yaml) check_file_copyright_header_winget_manifests "${file}" ;;
     *) check_file_copyright_header_quick_lint_js "${file}" ;;
   esac
@@ -37,13 +36,6 @@ check_file_copyright_header_winget_manifests() {
     fgrep -q 'quick-lint-js winget manifests' "${file}"
 }
 
-# quick-lint-js's benchmark-lsp subproject is BSD3-licensed.
-check_file_copyright_header_benchmark_lsp() {
-  local file="${1}"
-  fgrep -q 'Copyright' "${file}" && \
-    fgrep -q 'This file is part of quick-lint-js.' "${file}"
-}
-
 error=0
 for file in $(find_non_vendor_files | matching '(\<CMakeLists\.txt|\.bt|\.c|\.cmake|\.cpp|\.go|\.gperf|\.h|\.hs|\.html|\.js|\.lua|\.mjs|\.nix|\.po|\.pot|\.py|\.sh|\.vim|\.yaml|\.yml)$'); do
   if ! check_file_copyright_header "${file}"; then