Fixes #6236 - clarify non-Windows behavior

[sdwheeler]

PR Summary

Fixes AB#1750721

• Fixes Do not recommend -UseNewEnvironment in connection with -Wait, clarify -UseNewEnvironment behavior #6236 - clarify non-Windows behavior
• Fixes The Start-Process topic contains incorrect and misleading information about use on Unix-like platforms #3013

PR Context

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[opbld32]

Docs Build status updates of commit 79aac78:

✅ Validation status: passed

File	Status	Preview URL	Details
reference/5.1/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/6/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/7.0/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/7.1/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded

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[opbld32]

Docs Build status updates of commit e1354a6:

✅ Validation status: passed

File	Status	Preview URL	Details
reference/5.1/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/6/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/7.0/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/7.1/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded

For more details, please refer to the build report.

Note: Broken links written as relative paths are included in the above build report. For broken links written as absolute paths or external URLs, see the broken link report.

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[opbld31]

Docs Build status updates of commit 222bbba:

✅ Validation status: passed

File	Status	Preview URL	Details
reference/5.1/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/6/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/7.0/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/7.1/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded

For more details, please refer to the build report.

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[opbld30]

Docs Build status updates of commit 222bbba:

✅ Validation status: passed

File	Status	Preview URL	Details
reference/5.1/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/6/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/7.0/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded
reference/7.1/Microsoft.PowerShell.Management/Start-Process.md	✅Succeeded

For more details, please refer to the build report.

Note: Broken links written as relative paths are included in the above build report. For broken links written as absolute paths or external URLs, see the broken link report.

For any questions, please:

• Try searching in the Docs contributor and Admin Guide
• See the frequently asked questions
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