C135357: Fixing CDATA formatting (#3422)

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.Numerics/BigInteger.xml

@@ -6630,8 +6630,7 @@ value Mod 2 = 0
         <summary>Converts the representation of a number, contained in the specified read-only span of characters, in a specified style to its <see cref="T:System.Numerics.BigInteger" /> equivalent.</summary>
         <returns>A value that is equivalent to the number specified in the <paramref name="value" /> parameter.</returns>
         <remarks>
-          <format type="text/markdown">
-            <![CDATA[
+          <format type="text/markdown"><![CDATA[
 
 ## Remarks
 
@@ -7757,8 +7756,7 @@ The integer value `33022` can be exported in four different arrays:
         <summary>Tries to convert the string representation of a number to its <see cref="T:System.Numerics.BigInteger" /> equivalent, and returns a value that indicates whether the conversion succeeded.</summary>
         <returns><see langword="true" /> if <paramref name="value" /> was converted successfully; otherwise, <see langword="false" />.</returns>
         <remarks>
-          <format type="text/markdown">
-  <![CDATA[
+          <format type="text/markdown"><![CDATA[
 
 ## Remarks