Added user-friendly installation instructions

[admercs]

PR Summary

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Change is not breaking
• Make sure all .cs, .ps1 and .psm1 files have the correct copyright header
• Make sure you've added a new test if existing tests do not effectively test the code changed and/or updated documentation
• This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: to the beginning of the title and remove the prefix when the PR is ready.

[Copilot]

Pull Request Overview

This PR adds inline PowerShell commands to the README.md file to provide users with a quick installation method for PSScriptAnalyzer directly from the documentation, complementing the existing link to the detailed installation guide.

• Added inline PowerShell code snippet for installing PSScriptAnalyzer from PowerShell Gallery
• Provided command to set PSGallery as a trusted repository before installation

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[Copilot]

Setting the PSGallery repository to "Trusted" globally is a security risk and should not be recommended in installation instructions. This bypasses PowerShell's security prompts for package installations from PSGallery.

Instead, either:

1. Remove the Set-PSRepository line entirely and let users respond to the interactive prompt when running Install-Module, or
2. Use the -Force parameter with Install-Module to bypass the prompt for this specific installation only:

Install-Module -Name PSScriptAnalyzer -Force

Suggested change

Set-PSRepository -Name PSGallery -InstallationPolicy Trusted

[Copilot]

The -Scope parameter should be specified for Install-Module to clarify where the module will be installed. Without it, PowerShell will attempt to install to AllUsers scope which requires elevated permissions, potentially causing the command to fail for non-admin users.

Consider updating to:

Install-Module -Name PSScriptAnalyzer -Scope CurrentUser

This allows users to install the module without requiring administrator privileges.

Suggested change

	Install-Module -Name PSScriptAnalyzer
	Install-Module -Name PSScriptAnalyzer -Scope CurrentUser