Update intro text

Author: fspaolo

intro_hdf5_is2_files/Intro-HDF5-ICESat2-Files.ipynb

@@ -8,7 +8,7 @@
     "\n",
     "## What's HDF5?\n",
     "\n",
-    "* A file format optimized for numerical data\n",
+    "* A file format optimized for numeric data\n",
     "* A hierarquichal structure to store information (like folders)\n",
     "* A self-describing container: Metadata + Data\n",
     "* A library with several functionalities (tools)\n",