Announce terminal to screen reader

Part of #8339

package.json

@@ -45,7 +45,7 @@
     "vscode-debugprotocol": "1.25.0",
     "vscode-ripgrep": "^0.7.1-patch.0",
     "vscode-textmate": "^3.2.0",
-    "vscode-xterm": "3.1.0-beta5",
+    "vscode-xterm": "3.1.0-beta6",
     "yauzl": "2.8.0"
   },
   "devDependencies": {

yarn.lock

@@ -5808,9 +5808,9 @@ vscode-textmate@^3.2.0:
     fast-plist "^0.1.2"
     oniguruma "^6.0.1"
 
-vscode-xterm@3.1.0-beta5:
-  version "3.1.0-beta5"
-  resolved "https://registry.yarnpkg.com/vscode-xterm/-/vscode-xterm-3.1.0-beta5.tgz#b63c48cacda9c2546f50de550fef973a24df284c"
+vscode-xterm@3.1.0-beta6:
+  version "3.1.0-beta6"
+  resolved "https://registry.yarnpkg.com/vscode-xterm/-/vscode-xterm-3.1.0-beta6.tgz#0ff44249ac141e9f6dbcf0b7628d0b8d87e69abf"
 
 vso-node-api@^6.1.2-preview:
   version "6.1.2-preview"