Update typo in a warning message.

Author: josiahjohnston

switch_model/generators/core/dispatch.py

@@ -294,8 +294,8 @@ def _warn_on_extra_VARIABLE_GEN_TPS(m):
             "the scheduled operational dates. If you expect those datapoints "
             "to be useful, then those plants need to either come online "
             "earlier, have longer lifetimes, or have options to build new "
-            "new capacity when the old capacity reaches the provided "
-            "end-of-life date."
+            "capacity when the old capacity reaches the provided end-of-life "
+            "date."
             "\n".format(num_impacted_generators))
         if extra_indexes:
             logging.warning(warning_msg)