Merge pull request dotnet#8732 from svick/patch-1

Clarify UnicodeCategory.DecimalDigitNumber description

Author: tarekgh

xml/System.Globalization/UnicodeCategory.xml

@@ -345,7 +345,7 @@
       </ReturnValue>
       <MemberValue>8</MemberValue>
       <Docs>
-        <summary>Decimal digit character, that is, a character in the range 0 through 9. Signified by the Unicode designation "Nd" (number, decimal digit). The value is 8.</summary>
+        <summary>Decimal digit character, that is, a character representing an integer in the range 0 through 9. Signified by the Unicode designation "Nd" (number, decimal digit). The value is 8.</summary>
       </Docs>
     </Member>
     <Member MemberName="EnclosingMark">