Split layout and style docs, add style attribute table (#3534)

* Split layout and style widgets

Split the "Layout and Style" doc notebook into two, as it was quite large, and overly dominated by content on layout.

* Add tables about styles + attributes

Note that the cells generating the tables are hidden in nbsphinx!

* I meant to hide input, not full cell!

* Include new doc notebooks in index

* Fix top header for styling notebook

* Merge the tags input example file into the widget list file where all the other widgets are.

* Change the IntInputs default format to 'd', suitable for integers.

I found it confusing that the default format for integers looked like a floating point number.

Co-authored-by: Jason Grout <[email protected]>

Author: vidartf

docs/source/examples/Widget Layout.ipynb

@@ -999,14 +999,16 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Tags input widget"
+    "## Tag widgets"
    ]
   },
   {
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "The `TagsInput` widget is useful to for selecting/creating a list of tags. You can drag and drop tags to reorder them, limit them to a set of allowed values, or even prevent making duplicate tags."
+    "### TagsInput\n",
+    "\n",
+    "The `TagsInput` widget is useful for selecting/creating a list of tags. You can drag and drop tags to reorder them, limit them to a set of allowed values, or even prevent making duplicate tags."
    ]
   },
   {
@@ -1023,6 +1025,15 @@
     "tags"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### ColorsInput\n",
+    "\n",
+    "The `ColorsInput` widget is useful for selecting/creating a list of colors. You can drag and drop colors to reorder them, limit them to a set of allowed values, or even prevent making duplicate colors."
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -1037,6 +1048,44 @@
     "color_tags"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### Float and Integer Input widgets\n",
+    "\n",
+    "The `FloatInputs` and `IntsInput` widgets enable creating a list of float or integer numbers."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "floatsinput = widgets.FloatsInput(\n",
+    "    value=[1.3, 4.56, 78.90],\n",
+    "    tag_style='info',\n",
+    "    format = '.2f'\n",
+    ")\n",
+    "floatsinput"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "intsinput = widgets.IntsInput(\n",
+    "    value=[1, 4, 3243],\n",
+    "    min=0,\n",
+    "    max=1000000,\n",
+    "    format='$,d'\n",
+    ")\n",
+    "intsinput"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},