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

Start by examining the PowerShell module CI checks and reproduce the reported case using elif where PowerShell expects elseif. Compare the resulting diagnostic with the intended syntax-error report; done means this misuse is detected by CI instead of being reported only as unused variables.