Update TextElementEnumerator.xml (dotnet#32)

fix description of surrogate pairs

Author: srayuws

xml/System.Globalization/TextElementEnumerator.xml

@@ -48,7 +48,7 @@
  
 - A combining character sequence, which consists of a base character and one or more combining characters. For example, example, LATIN CAPITAL LETTER A (U+0041) followed by COMBINING MACRON (U+0304) is a combining character sequence. 
  
-- Surrogate pairs, which the [Unicode Standard](http://go.microsoft.com/fwlink/?linkid=37123) defines as a coded character representation for a single abstract character that consists of a sequence of two code units: a high surrogate, and a low surrogate. Surrogate pairs are used to represent characters outside of the Unicode Basic Multilingual Plane as UTF-8 encoded characters. For example, GOTHIC LETTER SAUIL (U+10343) is represented in UTF-8 encoding as a high surrogate whose value is 0xD800 and a low surrogate whose value is 0xDF43. A surrogate pair can represent a base character or a combining character. 
+- Surrogate pairs, which the [Unicode Standard](http://go.microsoft.com/fwlink/?linkid=37123) defines as a coded character representation for a single abstract character that consists of a sequence of two code units: a high surrogate, and a low surrogate. Surrogate pairs are used to represent characters outside of the Unicode Basic Multilingual Plane as UTF-16 encoded characters. For example, GOTHIC LETTER SAUIL (U+10343) is represented in UTF-16 encoding as a high surrogate whose value is 0xD800 and a low surrogate whose value is 0xDF43. A surrogate pair can represent a base character or a combining character. 
  
  The <xref:System.Globalization.TextElementEnumerator> class allows you to work with the text elements in a string rather than with single <xref:System.Char> objects. 
  
@@ -319,4 +319,4 @@
  </Docs>
  </Member>
  </Members>
-</Type>
+</Type>