change wording in custom handlers

Author: isabelizimm

docs/source/advancedusage/custom_handler.md

@@ -8,7 +8,7 @@ This example shows a custom handler of `newmodeltype` type.
 from vetiver.handlers.base import BaseHandler
 
 class CustomHandler(BaseHandler):
-    def __init__(model, ptype_data):
+    def __init__(self, model, ptype_data):
         super().__init__(model, ptype_data)
 
     model_type = staticmethod(lambda: newmodeltype)

docs/source/index.rst

@@ -10,7 +10,7 @@ You can install the released version of vetiver from `PyPI <https://pypi.org/pro
 
 .. code-block:: bash
 
-   pip install vetiver
+   python -m pip install vetiver
 
 And the development version from `GitHub <https://github.com/rstudio/vetiver-python>`_ with: