Add editor options for plain text mode and to disable block folding to

workaround rendering speed issues in CodeMirror with very large scripts.
Fixes #4631.

Re-arrange editor options in the Preferences dialogue to tidy things up.

web/pgadmin/tools/debugger/static/js/direct.js

@@ -1792,14 +1792,7 @@ define([
           foldOptions: {
             widget: '\u2026',
           },
-          foldGutter: {
-            rangeFinder: CodeMirror.fold.combine(
-              CodeMirror.pgadminBeginRangeFinder,
-              CodeMirror.pgadminIfRangeFinder,
-              CodeMirror.pgadminLoopRangeFinder,
-              CodeMirror.pgadminCaseRangeFinder
-            ),
-          },
+          foldGutter: true,
           gutters: [
             'CodeMirror-linenumbers', 'CodeMirror-foldgutter', 'breakpoints',
           ],