check: Use Git attributes to exclude files from the spell checker

.gitattributes

 *.webm filter=lfs diff=lfs merge=lfs -text
 *.mp4 filter=lfs diff=lfs merge=lfs -text
+/doc.zih.tu-dresden.de/docs/accessibility.md -check-spelling
+/doc.zih.tu-dresden.de/docs/data_protection_declaration.md -check-spelling
+/doc.zih.tu-dresden.de/docs/legal_notice.md -check-spelling
+/doc.zih.tu-dresden.de/docs/access/key_fingerprints.md -check-spelling

doc.zih.tu-dresden.de/util/check-spelling.sh

@@ -7,12 +7,6 @@ basedir=`dirname "${scriptpath}"`
 basedir=`dirname "${basedir}"`
 wordlistfile=$(realpath ${basedir}/wordlist.aspell)
 branch="origin/${CI_MERGE_REQUEST_TARGET_BRANCH_NAME:-preview}"
-files_to_skip=(
-doc.zih.tu-dresden.de/docs/accessibility.md
-doc.zih.tu-dresden.de/docs/data_protection_declaration.md
-doc.zih.tu-dresden.de/docs/legal_notice.md
-doc.zih.tu-dresden.de/docs/access/key_fingerprints.md
-)
 aspellmode=
 if aspell dump modes | grep -q markdown; then
   aspellmode="--mode=markdown"
@@ -46,7 +40,8 @@ function is_wordlist_sorted(){
 }
 
 function should_skip_file(){
-  printf '%s\n' "${files_to_skip[@]}" | grep -xq $1
+  local result="$(git check-attr check-spelling -- "$1")"
+  test "${result#*: check-spelling: }" = "unset"
 }
 
 function check_all_files(){