Open-dragon (microsoft#219848)

update known variables

Author: benibenj

build/lib/stylelint/vscode-known-variables.json

@@ -339,7 +339,7 @@
 		"--vscode-icon-foreground",
 		"--vscode-inlineChat-background",
 		"--vscode-inlineChat-border",
-		"--vscode-inlineChat-regionHighlight",
+		"--vscode-inlineChat-foreground",
 		"--vscode-inlineChat-shadow",
 		"--vscode-inlineChatDiff-inserted",
 		"--vscode-inlineChatDiff-removed",