Quote the variables in i3-sensible-* correctly

Previously, the variables $EDITOR, $PAGER, $TERMINAL and $VISUAL got
shell-expanded twice before executing them.

i3-sensible-pager

@@ -11,8 +11,8 @@
 # Hopefully one of these is installed (no flamewars about preference please!):
 # We don't use 'more' because it will exit if the file is too short.
 # Worst case scenario we'll open the file in your editor.
-for pager in $PAGER less most w3m pg i3-sensible-editor; do
-    if command -v $pager > /dev/null 2>&1; then
-        exec $pager "$@"
+for pager in "$PAGER" less most w3m pg i3-sensible-editor; do
+    if command -v "$pager" > /dev/null 2>&1; then
+        exec "$pager" "$@"
     fi
 done