header typo

Author: jeffjennings

tutorials/wcs-celestial-coords1/celestial_coords1.ipynb

@@ -20,7 +20,7 @@
     "\n",
     "WCS, coordinates, matplotlib\n",
     "\n",
-    "## Companion Contents\n",
+    "## Companion Content\n",
     "1. \"An Introduction to Modern Astrophysics\" ([Carroll & Ostlie](https://ui.adsabs.harvard.edu/abs/2006ima..book.....C/abstract))\n",
     "2. [FITS WCS page at GSFC](https://fits.gsfc.nasa.gov/fits_wcs.html)\n",
     "\n",