Add completion for paths

misc/bash/completion.sh

@@ -1,6 +1,14 @@
 function _complete_nix {
+    local have_type
     while IFS= read -r line; do
-        COMPREPLY+=("$line")
+        if [[ -z $have_type ]]; then
+            have_type=1
+            if [[ $line = filenames ]]; then
+                compopt -o filenames
+            fi
+        else
+            COMPREPLY+=("$line")
+        fi
     done < <(NIX_GET_COMPLETIONS=$COMP_CWORD "${COMP_WORDS[@]}")
 }