Add some more "handler" docs

app handler, batch handlers, native batch types, people handler

docs/data/batch/native/pricing.rst

@@ -0,0 +1,22 @@
+
+Pricing Batch
+=============
+
+**Batch Type Key:** ``pricing``
+
+**Purpose:** Change pricing for a set of products, optionally calculating new prices.
+
+**Default Handler:** :class:`~rattail:rattail.batch.pricing.PricingBatchHandler`
+
+There are sort of 2 modes for this batch type:
+
+In "static" mode you would have a data file containing the new prices,
+which you upload as a new batch.  Executing this batch would then
+apply the prices from the file.
+
+In "dynamic" mode you need only identify the set of products, and then
+let the software calculate new prices for each.  Executing this batch
+would then apply the new calculated prices.
+
+In either case the default handler will update Rattail itself, so you
+may need a custom handler to update your POS instead.