Fix various typos in the SocketsHttpHandler doc (#5012)

Author: mlaily

xml/System.Net.Http/SocketsHttpHandler.xml

@@ -596,15 +596,15 @@ For example, if the value is 64, then 65,536 bytes are allowed for the maximum r
         <ReturnType>System.TimeSpan</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>Gets or sets how long a connection can be the pool to be considered reusable.</summary>
+        <summary>Gets or sets how long a connection can be in the pool to be considered reusable.</summary>
         <value>The maximum time for a connection to be in the pool. The default value for this property is <see cref="F:System.Threading.Timeout.InfiniteTimeSpan" />.</value>
         <remarks>
           <format type="text/markdown"><![CDATA[
 
 ## Remarks
- This property define maximal connection lifetime in the pool regardles the connection is idle or active. The connection is reestablished periodically to reflect the DNS or other network changes.
+ This property defines maximal connection lifetime in the pool regardless of whether the connection is idle or active. The connection is reestablished periodically to reflect the DNS or other network changes.
  
- If the connection endpoint is not the Doamin name but the IP address, the value can be <xref:System.Threading.Timeout.InfiniteTimeSpan>.
+ If the connection endpoint is not the Domain name but the IP address, the value can be <xref:System.Threading.Timeout.InfiniteTimeSpan>.
 
  ]]></format>
         </remarks>