Issue #3455: powershell_script: do not allow suppression of syntax errors

[adamedx]

@ksubrama, @btm, @jdmundrawala thanks for merging #3080. Here's an addendum based on a few pieces of feedback I didn't follow up on:

1. Took @jdmundrawala 's feedback that preserving behavior of other script resources that let you suppress syntax errors just added complexity at the expense of obscuring a much more likely scenario: user expects a (failure) return code of 1, but the script itself has a syntax error. In that case, the script needs to be fixed by the user, but the user isn't aware because Chef reports no error. The powershell_script resource hasn't been around long enough to need such strict backwards compatibility to justify the complexity in code (evidenced by numerous questions in the Issue 2247: powershell_script exit status should be nonzero for syntax errors #3080 conversation) and the difficulty of the aforementioned scenario.
2. Feedback from @ksubrama and @jdmundrawala around it not being obvious how we were actually doing the syntax check by embedding user code in a PowerShell script block. That's actually the core idea of the syntax validation, so to make that more obvious, I've restructured the code generation string so that instead of a terse one-liner, it's in multiple lines and looks closer to how you'd write idiomatic PowerShell code where the block was more obvious.

[jaym]

👍

[ksubrama]

👍