Port System.Text.RegularExpressions source comments to Docs (#2311)

* Port System.Text.RegularExpressions source comments to Docs

* Update xml/System.Text.RegularExpressions/Regex.xml

So there's a rule stating we should always use "time-out"? Would you mind giving me the link?

Co-Authored-By: carlossanlop <[email protected]>

Author: carlossanlop

xml/System.Text.RegularExpressions/Regex.xml

@@ -5334,7 +5334,8 @@ Allows an <see cref="T:System.Object" /> to attempt to free resources and perfor
         <param name="matchTimeout">The time-out interval to check.</param>
         <summary>Checks whether a time-out interval is within an acceptable range.</summary>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentOutOfRangeException">The specified time-out is not within a valid range.</exception>
       </Docs>
     </Member>
   </Members>
-</Type>
+</Type>