PR Summary

This PR updates the PseudoBinding logic so there is a fallback to the session state if a function definition in the script text is broken for whatever reason.
This is intended as a workaround for the issue where you can't tab complete function parameters inside a script if the function uses a PowerShell class. Like in this scenario:

enum Animals
{
    Dog    = 0
    Cat    = 1
}
function Demo
{
    [OutputType([string])]
    Param
    (
        [Parameter()]
        [Animals]
        $Param1
    )
}

Demo -<Tab>
# or
(Demo).<Tab>

After this change you can load the class and function definitions into the session state (select them and press F8 in ISE/VS code) and now the tab completion will use the definitions found in the session state.

Ideally the PseudoBinding would be able to handle PowerShell classes in a scenario like this, but it relies on compiling the function definition, and when it does that it can't find the class.
I believe a proper fix would be to revamp the PseudoBinding so it doesn't have to compile the function definitions it finds, and can instead use static analysis of the function definition ast to determine the available parameters and output type. However, in the interest of reducing the workload for both me and the reviewer(s) <Looks at the 276 pending PRs> I have opted for this simple approach that can hopefully get through the process a little quicker.

PR Context

This fixes one of my main issues when working with PowerShell classes.

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge. If this PR is a work in progress, please open this as a Draft Pull Request and mark it as Ready to Review when it is ready to merge.
• Breaking changes
  • None
  • OR
  • Experimental feature(s) needed
    • Experimental feature name(s):
• User-facing changes
  • Not Applicable
  • OR
  • Documentation needed
    • Issue filed:
• Testing - New and feature
  • N/A or can only be tested interactively
  • OR
  • Make sure you've added a new test if existing tests do not effectively test the code changed