Fix Excel's Name Manager (workbook contains too many bad references in named ranges) issue

Fix-ExcelWorkbookXml.ps1

# Thanks to [Reddit](https://www.reddit.com/r/excel/comments/70r89w/need_to_delete_thousands_of_errored_named_ranges/i4huccg) 
# for the tip on resolving the name manager issue

# once you've extracted your XLSX file as a zip, find the `workbook.xml` file (should be under the `xl` subfolder)
$wbPath = 'C:\Temp\MyExtractedXlsx\xl\workbook.xml'

# open this XML file / parse it as XML
$wb = [xml](Get-Content -Path $wbPath -encoding UTF8 -Raw)

# find all `definedName` elements which contain the string `#REF!`.
$nodesToDelete = $wb.SelectNodes("/*[local-name()='workbook']/*[local-name()='definedNames']/*[local-name()='definedName' and ./text()[contains(.,'#REF!')]]")

# loop through these found names, removing each from the XML
foreach ($node in $nodesToDelete) {
    $node.ParentNode.RemoveChild($node) | Out-Null
}

# Save the XML again, overwriting the original with the updated copy
$wb.Save($wbPath)

# You can now zip the folder again (ensure that the folder's contents are the top level, rather than the zip file
# containing the parent folder too (i.e. the `xl` folder should show when you browse the zip's root directory instead
# of the zip containing the (e.g.) `MyExtractedXlsx` folder.
# Give this zipped copy the XLSX file extension then open it in Excel
# Save the workbook in Excel again (this will clean any entries which have been made redundant by our changes to workbook.xml).