feat: OpenXML.File.get_DocumentProperty ( Fixes #13 )

Author: StartAutomating

OpenXML.types.ps1xml

@@ -70,6 +70,22 @@ $excelCells
           </PropertySet>
         </Members>
       </MemberSet>
+      <AliasProperty>
+        <Name>DocProps</Name>
+        <ReferencedMemberName>DocumentProperty</ReferencedMemberName>
+      </AliasProperty>
+      <AliasProperty>
+        <Name>DocumentProperties</Name>
+        <ReferencedMemberName>DocumentProperty</ReferencedMemberName>
+      </AliasProperty>
+      <ScriptProperty>
+        <Name>DocumentProperty</Name>
+        <GetScriptBlock>
+                        if (-not $this.Parts) { return }
+$docProps = $this.Parts[$this.Parts.Keys -match '/docProps/']
+$docProps
+                    </GetScriptBlock>
+      </ScriptProperty>
       <NoteProperty>
         <Name>DefaultDisplay</Name>
         <Value>FilePath