Fix encoding of escape character in pwsh

Author: Tyriar

src/vs/workbench/contrib/terminal/browser/media/shellIntegration.ps1

@@ -52,17 +52,12 @@ if ($env:VSCODE_ENV_APPEND) {
 function Global:__VSCode-Escape-Value([string]$value) {
 	# NOTE: In PowerShell v6.1+, this can be written `$value -replace '…', { … }` instead of `[regex]::Replace`.
 	# Replace any non-alphanumeric characters.
-	$Result = [regex]::Replace($value, '[\\\n;]', { param($match)
+	[regex]::Replace($value, "[$([char]0x1b)\\\n;]", { param($match)
 			# Encode the (ascii) matches as `\x<hex>`
 			-Join (
 				[System.Text.Encoding]::UTF8.GetBytes($match.Value) | ForEach-Object { '\x{0:x2}' -f $_ }
 			)
 		})
-	# `e is only availabel in pwsh 6+
-	if ($PSVersionTable.PSVersion.Major -lt 6) {
-		$Result = $Result -replace "`e", '\x1b'
-	}
-	$Result
 }
 
 function Global:Prompt() {