LightboxItem Caption not passed to element & NavBar Sticky "top"

[germyparker]

Noticed a couple of very minor things:

data_caption

Adding a "data_caption" to a LightboxItem should pass its content to the caption once the lightbox is active:

# my code
        LightboxItem(
            Img(
                src=thumb_url,
            ),
            href=full_url,
            data_attrs=f"id: {m['id']}",
            data_caption=make_caption(m),
        )

Looks like it's declared in the inputs of the LightboxItem, but not returned:

# nbs/02_franken.ipynb:3437
    "def LightboxItem(*c, # Component that when clicked will open the lightbox (often a button)\n",
    "                 href, # Href to image, youtube video, vimeo, google maps, etc.\n",
    "                 data_alt=None, # Alt text for the lightbox item/image\n",
    "                 data_caption=None, # Caption for the item that shows below it\n",
    "                 cls='', # Class for the A tag (often nothing or `uk-btn`)\n",
    "                 **kwargs # Additional args for the `A` tag\n",
    "                )->FT: # A(... href, data_alt, cls., ...)\n",
    "    \"Anchor tag with appropriate structure to go inside a `LightBoxContainer`\"\n",
    "    return fh.A(*c, href=href, data_alt=data_alt, cls=stringify(cls), **kwargs)"

Adding it to the return seems to fix it:

    "    return fh.A(*c, href=href, data_alt=data_alt, data_caption=data_caption, cls=stringify(cls), **kwargs)"

NavBar sticky top

The top value that's associated with the sticky functionality for the NavBar places it at top-4:

# nbs/02_franken.ipynb:2339
    "    _sticky = 'float-left sticky top-4 hidden md:block' if sticky else ''\n",

This seems like it would not be the expected default behavior. Might be related to a difference in box-sizing settings? But I don't have any reset or css in addition to MonsterUI so I'm pretty sure I'm seeing it as it appears out of the box. So, anyway, I changed it to:

# nbs/02_franken.ipynb:2339
    "    _sticky = 'float-left sticky top-0 hidden md:block' if sticky else ''\n",

I saw the same top-4 value in the NavContainer component, but I haven't used that it so I'm not sure whether that's appropriate or not.

Thanks

I can put in a PR if you'd like.