Small doc update

- Remove center_middle example because it's no longer an allowed style
- Remove a few stray commented code snippets
- Reference `Scenic.Primitive.Style.TextAlign` in a spot where
  `:text_align` is mentioned for easier discovery
- Update a sample code to follow the Elixir Formatter's style

Author: axelson

lib/scenic/component.ex

@@ -210,12 +210,8 @@ defmodule Scenic.Component do
       # --------------------------------------------------------
       defoverridable add_to_graph: 3
     end
-
-    # quote
   end
 
-  # defmacro
-
   @filter_out [
     :cap,
     :fill,
@@ -240,7 +236,6 @@ defmodule Scenic.Component do
   # prepare the list of opts to send to a component as it is being started up
   # the main task is to remove styles that have already been consumed or don't make
   # sense, while leaving any opts/styles that are intended for the component itself.
-  # also, add the viewport as an option.
   @doc false
   @spec filter_opts(opts :: Keyword.t()) :: Keyword.t()
   def filter_opts(opts) when is_list(opts) do

lib/scenic/graph.ex

@@ -68,8 +68,9 @@ defmodule Scenic.Graph do
   that new primitives added to it are inserted into the new group instead of the
   root of the graph.
 
-  Finally, when the group is finished, a translation matrix and a `:text_align` style
-  are added to it. These properties are _inherited_ by the primitives in the group.
+  Finally, when the group is finished, a translation matrix and a `:text_align`
+  style (see `Scenic.Primitive.Style.TextAlign`) are added to it. These
+  properties are _inherited_ by the primitives in the group.
 
   ## Inheritance
 

lib/scenic/primitive/style/text_align.ex

@@ -11,7 +11,7 @@ defmodule Scenic.Primitive.Style.TextAlign do
 
   ```elixir
   graph
-    |> text( "Some Text", text_align: :center_middle )
+  |> text("Some Text", text_align: :center)
   ```
 
   ### Data Format

lib/scenic/primitives.ex

@@ -1195,8 +1195,8 @@ defmodule Scenic.Primitives do
     then draw it again without blur, slightly offset, you get a nice drop shadow
     effect. The default is to draw with no blur.
   * `:text_align` - Specify the alignment of the text you are drawing. You will
-    usually specify one of: `:left`, `:center`, or `:right`. You can also specify
-    vertical alignment. See `Scenic.Primitive.Style.TextAlign` for details.
+    usually specify one of: `:left`, `:center`, or `:right`. See
+    `Scenic.Primitive.Style.TextAlign` for details.
   * `:text_height` - Specify the vertical spacing between rows of text.