Add some more comments on API functions

Just filling in some of the holes in documentation. Long term, it would
be better to cut down these comments and put more effort into the
project wiki, I think.

src/Panda/Builders/Components.purs

@@ -494,6 +494,9 @@ make tagName properties children
       , children
       }
 
+-- | Make a "collection" element from some container. These are collections in
+-- | the Panda sense - element containers that are open to incremental updates.
+
 collection ∷ String → Collection
 collection tagName properties watcher
   = Types.Collection

src/Panda/Builders/Property/Watchers.purs

@@ -2,6 +2,10 @@ module Panda.Builders.Property.Watchers where
 
 import Panda.Internal.Types as Types
 
+-- | Watch for changes in state and update accordingly. Note that adding a
+-- | property will remove any previously-set properties, so it is advised that
+-- | you use independent `watch` values for each property that is dynamic.
+
 watch
   ∷ ∀ update state event
   . ( { update ∷ update, state ∷ state }
@@ -12,6 +16,9 @@ watch
 watch listener
   = Types.Dynamic listener
 
+-- | Given a predicate on the state and update, this function will recompute a
+-- | value whenever the predicate yields true.
+
 when
   ∷ ∀ update state event
   . ({ update ∷ update, state ∷ state } → Boolean)

src/Panda/Incremental/Collection.purs

@@ -10,13 +10,18 @@ import Panda.Internal.Types      as Types
 
 import Panda.Prelude
 
+-- | Convenience synonym for incremental renderers.
+
 type Renderer update state event
   = Types.Component update state event
   → Effect
       { node   ∷ DOM.Node
       , system ∷ Maybe (Types.EventSystem update state event)
       }
 
+-- | Execute an incremental `update` on the children of some `parent`, along
+-- | with their `systems`, and `render` any new inserts.
+
 execute
   ∷ ∀ update state event
   . { parent   ∷ DOM.Node

src/Panda/Render/Component.purs

@@ -17,6 +17,9 @@ import Partial.Unsafe               (unsafePartial)
 
 import Panda.Prelude
 
+-- | Given a DOM document and a bootstrapping function, render a component to
+-- | a DOM node, along with the corresponding event system.
+
 render
   ∷ ∀ update state event
   . DOM.Document

src/Panda/Render/Property.purs

@@ -184,6 +184,10 @@ renderDynamic element watcher = do
               effToEffect (Ref.writeRef propertyRef updated)
     }
 
+-- | Given an element, along with some property DSL value, render the
+-- | calculated property to the element, which may involve some handling of
+-- | event listeners.
+
 render
   ∷ ∀ update state event
   . DOM.Element