update history formatting

History.md

@@ -2,8 +2,10 @@
 This document maintains a list of changes to Slate with each new version. Until `1.0.0` is released, breaking changes will be added as minor version bumps, and non-breaking changes won't be accounted for since the library is moving quickly.
 
 
-## `0.5.0`
-_July 20, 2016_
+---
+
+
+### `0.5.0` — _July 20, 2016_
 
 #### BREAKING CHANGES
 
@@ -12,32 +14,28 @@ _July 20, 2016_
 - **`Node` methods now `throw` earlier during unexpected states.** This shouldn't break anything for most folks, unless a strange edge-case was going undetected previously.
 
 
-## `0.4.0`
-_July 20, 2016_
+### `0.4.0` — _July 20, 2016_
 
 #### BREAKING CHANGES
 
 - **`renderMark(mark, state, editor)` is now `renderMark(mark, marks, state, editor)`.** This change allows you to render marks based on multiple `marks` presence at once on a given range of text, for example using a custom `BoldItalic.otf` font when text has both `bold` and `italic` marks.
 
 
-## `0.3.0`
-_July 20, 2016_
+### `0.3.0` — _July 20, 2016_
 
 #### BREAKING CHANGES
 
 - **`transform.unwrapBlock()` now unwraps selectively.** Previously, calling `unwrapBlock` with a range representing a middle sibling would unwrap _all_ of the siblings, removing the wrapping block entirely. Now, calling it with those same arguments will only move the middle sibling up a layer in the hierarchy, preserving the nesting on any of its siblings. This changes makes it much simpler to implement functionality like unwrapping a single list item, which previously would unwrap the entire list.
 
 
-## `0.2.0`
-_July 18, 2016_
+### `0.2.0` — _July 18, 2016_
 
 #### BREAKING CHANGES
 
 - **`transform.mark()` is now `transform.addMark()` and `transform.unmark()` is now `transform.removeMark()`.** The new names make it clearer that the transforms are actions being performed, and it paves the way for adding a `toggleMark` convenience as well.
 
 
-## `0.1.0`
-_July 13, 2016_
+### `0.1.0` — _July 13, 2016_
 
 :tada: