fixup! refactor: adapt and simplify filetypes.sh

Author: gegoune

scripts/filetypes.sh

@@ -3,9 +3,7 @@
 # Iterate over the elements of icons_by_file_extension and check if there are missed filetypes.
 # $VIMRUNTIME specifies neovim runtime path, defaults to "/usr/share/nvim/runtime" if unset.
 
-if [ -z "${VIMRUNTIME}" ]; then
-  export VIMRUNTIME="/usr/share/nvim/runtime"
-fi
+: "${VIMRUNTIME:=/usr/share/nvim/runtime}"
 
 exit_value=0