fish: functions/dotg: Do not add dot to output file name

If a file name was foo.dot the current implementation generated a
foo.dot.svg. Fix it to just output a foo.svg.

Also fix a bug, where we were not considering the provided dotpath.

fish/.config/fish/functions/dotg.fish

@@ -5,10 +5,11 @@ function dotg --description 'Generate gstreamer dot graph for selected file'
         set dotpath "$GST_DEBUG_DUMP_DOT_DIR"
     end
 
-    find /tmp/gst-dot -maxdepth 1 -regextype posix-extended -regex ".*\.(dot)" -printf '%T@ %p\n' | sort -k 1 -n -r | fzf --bind "ctrl-d:half-page-down,ctrl-u:half-page-up" | awk -F' ' '{print $2}' | read -l result
+    find $dotpath -maxdepth 1 -regextype posix-extended -regex ".*\.(dot)" -printf '%T@ %p\n' | sort -k 1 -n -r | fzf --bind "ctrl-d:half-page-down,ctrl-u:half-page-up" | awk -F' ' '{print $2}' | read -l result
 
     if test -n "$result"
-        dot -Tsvg "$result" -O
-        mv "$result".svg ~/Pictures/gstreamer
+        set filename (echo $result | sed 's/\.[^.]*$//')
+        dot -Tsvg "$result" -o "$filename".svg
+        mv "$filename".svg ~/Pictures/gstreamer
     end
 end