more robust: avoid breakdown of Search dialog;

--- a/src/Tools/VSCode/extension/package.json	Fri Mar 11 13:44:13 2022 +0100
+++ b/src/Tools/VSCode/extension/package.json	Fri Mar 11 14:02:13 2022 +0100
@@ -170,6 +170,14 @@
                 "configuration": "./isabelle-ml-language.json"
             }
         ],
+        "configurationDefaults": {
+          "[isabelle]": {
+            "files.encoding": "utf8isabelle"
+          },
+          "[isabelle-ml]": {
+            "files.encoding": "utf8isabelle"
+          }
+        },
         "grammars": [
             {
                 "language": "isabelle",

--- a/src/Tools/VSCode/src/vscode_setup.scala	Fri Mar 11 13:44:13 2022 +0100
+++ b/src/Tools/VSCode/src/vscode_setup.scala	Fri Mar 11 14:02:13 2022 +0100
@@ -26,7 +26,6 @@
     "editor.unicodeHighlight.ambiguousCharacters": false,
     "extensions.autoCheckUpdates": false,
     "extensions.autoUpdate": false,
-    "files.encoding": "utf8isabelle",
     "terminal.integrated.fontFamily": "monospace",
     "update.mode": "none"
   }