Fix markdown lint issues

prebid/native-implementation-legacy.md

@@ -52,6 +52,7 @@ This table summarizes how the 3 approaches work:
 **Table 1: Native Implementation Approaches**
 
 {: .table .table-bordered .table-striped }
+
 | Component | AdServer-Defined Creative Scenario | AdUnit-Defined Creative Scenario | Custom Renderer Scenario |
 | --- | --- |--- | --- |
 | Prebid.js | mediaTypes. native.sendTargetingKeys: false | sendTargetingKeys:false and mediaTypes.native.adTemplate contains ##macros## | sendTargetingKeys:false and mediaTypes.native.rendererUrl |
@@ -67,6 +68,7 @@ The Prebid.js AdUnit needs to defines a native mediatype object to tell bidders
 **Table 2: Prebid.js AdUnit Native MediaType Options**
 
 {: .table .table-bordered .table-striped }
+
 | Attribute | Scope | Description | Example | Type |
 | --- | --- | --- | --- | --- |
 | sendTargetingKeys | optional | Defines whether or not to send the hb_native_ASSET targeting keys to the ad server. Defaults to `true` for now, though we recommend setting this to `false` and utilizing one of the ways to define a native template. | `false` | boolean |

prebid/prebidjsReleases.md

@@ -14,6 +14,7 @@ the [GitHub releases page](https://github.com/prebid/Prebid.js/releases) can be
 The table below is a summary of feature changes and important bug fixes in core of Prebid.js. Almost [all releases](https://github.com/prebid/Prebid.js/releases) have new bid adapters or updates to existing adapters -- what's listed here is limited to core functionality. Releases with only minor core changes may not be shown here, and releases with multiple important changes may be shown more than once.
 
 {: .table .table-bordered .table-striped }
+
 | Release | Feature |
 | --- | --- |
 | 8.0 | Module removals, reliabe (opt-in) transaction identifier, size mapping module & acitivy control. See the [PBJS 8 release notes](/dev-docs/pb8-notes.html) |