smarter mimetype matching

rc/base/file.kak

@@ -3,9 +3,12 @@ decl str mimetype
 hook global BufOpen .* %{ %sh{
     if [ -z "${kak_opt_filetype}" ]; then
         mime=$(file -b --mime-type "${kak_buffile}")
-        printf %s\\n "${mime}" | grep -q '^text/x-'
-        if [ $? -eq 0 ]; then
-            printf "set buffer filetype '%s'\n" "${mime:7}"
+        case "${mime}" in
+            text/x-*) filetype="${mime#text/x-}" ;;
+            text/*)   filetype="${mime#text/}" ;;
+        esac
+        if [ -n "${filetype}" ]; then
+            printf "set buffer filetype '%s'\n" "${filetype}"
         else
             printf "set buffer mimetype '%s'\n" "${mime}"
         fi