Add new rule to catch syntax error e.g. "elif" instead of "elseif"

Summary of the new feature

Try formulating it in user story style (if applicable):
'As a python and powershell developer I want ScriptAnalyzer to detect when I use elif (python) instead of elseif (powershell) so that the ci warns me about invalid statements and I can correct the code.'

Proposed technical implementation details (optional)

For powershell modules we need an additional ci check. Currently syntax errors are not always covered. The ci for example does currently not cover usage of elif instead of elseif (former is python later is powershell).

Example shippables: https://app.shippable.com/github/ansible/ansible/runs/133592/1/console (source)
It erroneously reports unused variables instead of a syntax error.

What is the latest version of PSScriptAnalyzer at the point of writing

Beginne damit, die CI-Prüfungen für das PowerShell-Modul zu untersuchen, und reproduziere den gemeldeten Fall, indem du elif verwendest, wo PowerShell elseif erwartet. Vergleiche die resultierende Diagnose mit der vorgesehenen Meldung eines Syntaxfehlers; abgeschlossen ist die Aufgabe, wenn dieser Missbrauch von CI erkannt wird, anstatt nur als unbenutzte Variablen gemeldet zu werden.