Meta CHANGELOG markdown cleanup.

(Prefered style is to surround lists with blank lines.)

Change-Id: I96e5d6715e056e3dd531059e86262e1028b51209
Reviewed-on: https://dart-review.googlesource.com/53689
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>

pkg/meta/CHANGELOG.md

@@ -12,9 +12,11 @@
 * Rollback SDK constraint update for 2.0.0. No longer needed.
 
 ## 1.1.1
+
 * Update SDK constraint to be 2.0.0 dev friendly.
 
 ## 1.1.0
+
 * Introduce `@alwaysThrows` to declare that a function always throws
     (SDK issue [17999](https://github.com/dart-lang/sdk/issues/17999)). This
     is first available in Dart SDK 1.25.0-dev.1.0.
@@ -38,6 +40,7 @@
     ```
 
 ## 1.0.5
+
 * Introduce `@experimental` to annotate a library, or any declaration that is
   part of the public interface of a library (such as top-level members, class
   members, and function parameters) to indicate that the annotated API is
@@ -46,6 +49,7 @@
   be a breaking change.
 
 ## 1.0.4
+
 * Introduce `@virtual` to allow field overrides in strong mode
     (SDK issue [27384](https://github.com/dart-lang/sdk/issues/27384)).
 
@@ -64,6 +68,7 @@
     ```
 
 ## 1.0.3
+
 * Introduce `@checked` to override a method and tighten a parameter
     type (SDK issue [25578](https://github.com/dart-lang/sdk/issues/25578)).
 
@@ -84,34 +89,42 @@
     ```
 
 ## 1.0.2
+
 * Introduce `@visibleForTesting` annotation for declarations that may be referenced only in the library or in a test.
 
 ## 1.0.1
+
 * Updated `@factory` to allow statics and methods returning `null`.
 
 ## 1.0.0
+
 * First stable API release.
 
 ## 0.12.2
+
 * Updated `@protected` to include implemented interfaces (linter#252).
 
 ## 0.12.1
+
 * Fixed markdown in dartdocs.
 
 ## 0.12.0
+
 * Introduce `@optionalTypeArgs` annotation for classes whose type arguments are to be treated as optional.
 
 ## 0.11.0
+
 * Added new `Required` constructor with a means to specify a reason to explain why a parameter is required.
 
 ## 0.10.0
-* Introduce `@factory` annotation for methods that must either be abstract or
-must return a newly allocated object.
+
+* Introduce `@factory` annotation for methods that must either be abstract or must return a newly allocated object.
 * Introduce `@literal` annotation that indicates that any invocation of a
 constructor must use the keyword `const` unless one or more of the
 arguments to the constructor is not a compile-time constant.
 
 ## 0.9.0
+
 * Introduce `@protected` annotation for members that must only be called from
 instance members of subclasses.
 * Introduce `@required` annotation for optional parameters that should be treated