PR Summary

Fixes a few things about hashtable completion:

1. Use partial input to filter the suggested keys
2. Filters out keys that have already been specified in the hashtable
3. Allows hashtable key completion to happen on blank lines, even if a key/value pair was specified on an earlier line

Example of a scenario that currently fails, but will get fixed by this PR:

ls | sort @{
Expression={}
<Cursor here>
}

Also adds completers for the Arguments parameter for Invoke-CimMethod the FilterHashtable parameter for Get-WinEvent the Property Parameter for the cim cmdlets and the standard cim completers for Set-CimInstance.
This also removes duplicates from member completion in scenarios like ls | select Attributes,<Cursor here> this could be split off into its own PR but since it depends on changes made in this PR I thought I may as well include it here.
Finally it adds some basic completion support for hashtables used for splatting. The pseudo binding doesn't take the hashtable parameters into account so it's not perfect but IMO some completion is better than none.

Fixes #9239

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    • Impact on PowerShell Editor Services which is used in the PowerShell extension for VSCode
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