change show test utility function

Due to how various tests show the status of variables I decided to
modify the `show` test utility function I recently added.

tests/test_functions/show.fish

@@ -1,4 +1,14 @@
-function show
-    echo count=(count $argv)
-    printf '|%s|\n' $argv
+# Show information about the named var(s) passed to us.
+function show --no-scope-shadowing
+    for v in $argv
+        if set -q $v
+            set -l c (count $$v)
+            printf '$%s count=%d\n' $v $c
+            for i in (seq $c)
+                printf '$%s[%d]=|%s|\n' $v $i $$v[1][$i]
+            end
+        else
+            echo \$$v is not set
+        end
+    end
 end