docs(changelog): make labels and list style consistent

Remove 'Breaking Changes' label where there are no breaking changes.

Only for '1.4.0-rc.2', breaking changes have different styling (bold without bulleted list). Change to be consistent with others

(#14482)

Author: AbhishekGarg

CHANGELOG.md

@@ -1008,9 +1008,6 @@ is  `$locals`.
    [#13236](https://github.com/angular/angular.js/issues/13236))
 
 
-## Breaking Changes
-
-
 <a name="1.5.0-beta.2"></a>
 # 1.5.0-beta.2 effective-delegation (2015-11-17)
 
@@ -1330,9 +1327,6 @@ requirement more strict and alerts the developer explicitly.
    [#2318](https://github.com/angular/angular.js/issues/2318), [#9319](https://github.com/angular/angular.js/issues/9319), [#12159](https://github.com/angular/angular.js/issues/12159))
 
 
-## Breaking Changes
-
-
 <a name="1.3.20"></a>
 # 1.3.20 shallow-translucence (2015-09-29)
 
@@ -1343,9 +1337,6 @@ requirement more strict and alerts the developer explicitly.
   ([d434f3db](https://github.com/angular/angular.js/commit/d434f3db53d6209eb140b904e83bbde401686c16))
 
 
-## Breaking Changes
-
-
 <a name="1.2.29"></a>
 # 1.2.29 ultimate-deprecation (2015-09-29)
 
@@ -1372,9 +1363,6 @@ requirement more strict and alerts the developer explicitly.
    [#9936](https://github.com/angular/angular.js/issues/9936))
 
 
-## Breaking Changes
-
-
 <a name="1.4.6"></a>
 # 1.4.6 multiplicative-elevation (2015-09-17)
 
@@ -2203,9 +2191,7 @@ describe('$q.when', function() {
 
 ## Breaking Changes
 
-### ngAnimate
-
-- **$animateCss:** due to [d5683d21](https://github.com/angular/angular.js/commit/d5683d21165e725bc5a850e795f681b0a8a008f5),
+- **ngAnimate** - $animateCss: due to [d5683d21](https://github.com/angular/angular.js/commit/d5683d21165e725bc5a850e795f681b0a8a008f5),
   The $animateCss service will now always return an
 object even if the animation is not set to run. If your code is using
 $animateCss then please consider the following code change:
@@ -2289,9 +2275,7 @@ $animateProvider.classNameFilter(/ng-animate-special/);
 ```
 
 
-### ngOptions
-
-- ** due to [dfa722a8](https://github.com/angular/angular.js/commit/dfa722a8a6864793fd9580d8ae704a06d10b5509),
+- **ngOptions**: due to [dfa722a8](https://github.com/angular/angular.js/commit/dfa722a8a6864793fd9580d8ae704a06d10b5509),
 
 
 Although it is unlikely that anyone is using it in this way, this change does change the