L126374: Fixing CDATA formatting (#3308)

Localization team has reported source content issue that causes localized version to have broken/different format compared to en-us version.
Description: the Markdown CDATA content is incorrectly formatted in source files, moreover it is breaking the target publishing builds since the content inside those tags are being processed as XML tag instead of Markdown content.

Author: v-maudel

xml/System.Reflection.Metadata.Ecma335/SignatureDecoder`2.xml

@@ -29,8 +29,7 @@
     <typeparam name="TGenericContext">To be added.</typeparam>
     <summary>Decodes signature blobs.</summary>
     <remarks>
-      <format type="text/markdown">
-  <![CDATA[
+      <format type="text/markdown"><![CDATA[
 
 ## Remarks