Tweaked script field arg parsing to strip whitespace almost everywhere

The whitespace sensitivity of field args was starting to be a problem,
mostly for advanced plotmpl.py usage (which tbf might be appropriately
described as "super hacky" in how it uses CLI parameters):

  ./scripts/plotmpl.py \
      -Dcase=" \
          bench_rbyd_attr_append, \
          bench_rbyd_attr_remove, \
          bench_rbyd_attr_fetch, \
          ..."

This may present problems when parsing CSV files with whitespace, in
theory, maybe. But given the scope of these scripts for littlefs...
just don't do that. Thanks.

scripts/code.py

@@ -667,7 +667,11 @@ if __name__ == "__main__":
         '-D', '--define',
         dest='defines',
         action='append',
-        type=lambda x: (lambda k,v: (k, set(v.split(','))))(*x.split('=', 1)),
+        type=lambda x: (
+            lambda k, vs: (
+                k.strip(),
+                {v.strip() for v in vs.split(',')})
+            )(*x.split('=', 1)),
         help="Only include results where this field is this value.")
     class AppendSort(argparse.Action):
         def __call__(self, parser, namespace, value, option):