Clarify that the macro support we have

i.e. we are discussing supporting display math environment, rather than arbitrary macros (which in the broadest sense are not in any case supported by all our rendering backends)

render_math/Readme.md

@@ -129,17 +129,20 @@ must *not* be any whitespace before the ending `$`. So for example:
  * **Will not render as inline math**: `$40 vs $50`
 
 ###Displayed Math
-Math between `$$`..`$$`, for example, `$$`x^2`$$`, will be rendered centered in a
+Math between `$$`..`$$` will be rendered "block style", for example, `$$`x^2`$$`, will be rendered centered in a
 new paragraph.
 
-###Latex Macros
-Latex macros are supported, and are automatically treated like displayed math 
-(i.e. it is wrapped in `div` tag). For example, `begin{equation}` x^2 `\end{equation}`,
+####Other Latex  Display Math commands
+The other LaTeX commands which usually invoke display math mode from text mode
+are supported,
+and are automatically treated like `$$`-style displayed math 
+in that they are rendered "block" style on their own lines.
+For example, `begin{equation}` x^2 `\end{equation}`,
 will be rendered in its own block with a right justified equation number
 at the top of the block. This equation number can be referenced in the document.
 To do this, use a `label` inside of the equation format and then refer to that label
-using `ref`. For example: `begin{equation}` `\label{eq}` X^2 `\end{equation}`. Now
-refer to that equation number by `$`\ref{eq}`$`.
+using `ref`. For example: `begin{equation}` `\label{eq}` X^2 `\end{equation}`. 
+Now refer to that equation number by `$`\ref{eq}`$`.
 
 reStructuredText
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