Clarify FileShare enum descriptions to remove ambiguity

 Removed misleading word "subsequent" from FileShare enum member
  descriptions. The previous wording implied these flags only affect
  future file operations, but they actually control access for both
  the current file open operation and all other attempts to access
  the file.

  Updated all four affected members (Delete, Read, ReadWrite, Write)
  to use clearer language: "Allows the file to be opened..." instead
  of "Allows subsequent opening..."

  Fixes #10572

Author: oii-nasif

xml/System.IO/FileShare.xml

@@ -142,7 +142,7 @@
       </ReturnValue>
       <MemberValue>4</MemberValue>
       <Docs>
-        <summary>Allows subsequent deleting of a file.</summary>
+         <summary>Allows the file to be deleted by this process or other processes. The file can be deleted while it remains open.</summary>
       </Docs>
     </Member>
     <Member MemberName="Inheritable">
@@ -277,7 +277,7 @@
       </ReturnValue>
       <MemberValue>1</MemberValue>
       <Docs>
-        <summary>Allows subsequent opening of the file for reading. If this flag is not specified, any request to open the file for reading (by this process or another process) will fail until the file is closed. However, even if this flag is specified, additional permissions might still be needed to access the file.</summary>
+         <summary>Allows the file to be opened for reading by this process or other processes. If this flag is not specified, any request to open the file for reading (by this process or another process) will fail until the file is closed. However, even if this flag is specified, additional permissions might still be needed to access the file.</summary>
       </Docs>
     </Member>
     <Member MemberName="ReadWrite">
@@ -322,7 +322,7 @@
       </ReturnValue>
       <MemberValue>3</MemberValue>
       <Docs>
-        <summary>Allows subsequent opening of the file for reading or writing. If this flag is not specified, any request to open the file for reading or writing (by this process or another process) will fail until the file is closed. However, even if this flag is specified, additional permissions might still be needed to access the file.</summary>
+        <summary>Allows the file to be opened for reading or writing by this process or other processes. If this flag is not specified, any request to open the file for reading or writing (by this process or another process) will fail until the file is closed. However, even if this flag is specified, additional permissions might still be needed to access the file.</summary>
       </Docs>
     </Member>
     <Member MemberName="Write">
@@ -367,7 +367,7 @@
       </ReturnValue>
       <MemberValue>2</MemberValue>
       <Docs>
-        <summary>Allows subsequent opening of the file for writing. If this flag is not specified, any request to open the file for writing (by this process or another process) will fail until the file is closed. However, even if this flag is specified, additional permissions might still be needed to access the file.</summary>
+        <summary>Allows the file to be opened for writing by this process or other processes. If this flag is not specified, any request to open the file for writing (by this process or another process) will fail until the file is closed. However, even if this flag is specified, additional permissions might still be needed to access the file.</summary>
       </Docs>
     </Member>
   </Members>