docs: add missing examples/index.rst

Author: aleaf

docs/source/examples/index.rst

@@ -0,0 +1,13 @@
+========================================
+Using SFRmaker
+========================================
+
+.. toctree::
+   :maxdepth: 1
+   :caption: Examples
+
+   Using SFRmaker with a configuration file: MERAS 3 example <meras>
+   Using SFRmaker with a configuration file: Tyler Forks example <tf>
+   Using SFRMaker in a script <../notebooks/SFRmaker_demo>
+   Using SFRmaker with NHDPlus High Resolution <../notebooks/lines_from_NHDPlusHR_demo>
+   Converting a MODFLOW-2005 (SFR2) Package to MODFLOW 6 <../notebooks/mf5to6>