DOC: refer to sel. tut and |-searching from MP tut

closes #224. phew.

example_notebooks/moving_pictures/moving_pictures.ipynb

@@ -318,6 +318,10 @@
     "\n",
     "Now things are more populated! The sample plot has at least a few samples from each of the four body sites -- and we've managed to recapitulate the general pattern of sample separation we saw with the autoselection, but with a more targeted log-ratio between two genera.\n",
     "\n",
+    "#### Sidenote: using multiple features from Emperor in the same side of a log-ratio\n",
+    "\n",
+    "If you'd like, you can specify arbitrary amounts of feature IDs on one side of a log-ratio. This can be done by separating the IDs by `|` characters and using the `contains any text separated by | (pipe)` searching option; see the [Selection tutorial](https://nbviewer.jupyter.org/github/biocore/qurro/blob/master/example_notebooks/selection/selection.ipynb) for details.\n",
+    "\n",
     "### 5.3. Hey, wait a second! There are only eight arrows in the biplot, but there are over five hundred features in the rank plot. What gives?\n",
     "\n",
     "This is just a result of how the biplot visualization was created in the DEICODE tutorial. In the `qiime emperor biplot` command, the `--p-number-of-features` parameter was set to 8, so only 8 arrows (i.e. features) are shown in the Emperor visualization of the biplot. Feel free to try rerunning this command with a different number of features to show more features in the biplot.\n",
@@ -345,6 +349,13 @@
     "\n",
     "This tutorial was based on the [DEICODE](https://nbviewer.jupyter.org/github/biocore/DEICODE/blob/master/ipynb/tutorials/moving-pictures.ipynb) and [QIIME 2](https://docs.qiime2.org/2019.10/tutorials/moving-pictures/) moving pictures tutorials."
    ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
   }
  ],
  "metadata": {