Use json from legacy-modes

It seems that json is better highlighted under the legacy modes then
the modern lang-json package. We'll switch to legacy-modes for json
for now until it is fixed.

Change-Id: I53859c6d0343059470012e5dd836e3530aa0fbb0

web/element/language.ts

diff --git a/web/element/language.ts b/web/element/language.ts
index d26b034..ba76215 100644
--- a/web/element/language.ts
+++ b/web/element/language.ts
@@ -46,6 +46,7 @@
 import {http} from '@codemirror/legacy-modes/mode/http';
 import {idl} from '@codemirror/legacy-modes/mode/idl';
 import {jinja2} from '@codemirror/legacy-modes/mode/jinja2';
+import {json} from '@codemirror/legacy-modes/mode/javascript';
 import {jsonld} from '@codemirror/legacy-modes/mode/javascript';
 import {julia} from '@codemirror/legacy-modes/mode/julia';
 import {kotlin} from '@codemirror/legacy-modes/mode/clike';
@@ -110,7 +111,6 @@
 import {html} from '@codemirror/lang-html';
 import {java} from '@codemirror/lang-java';
 import {javascript} from '@codemirror/lang-javascript';
-import {json} from '@codemirror/lang-json';
 import {less} from '@codemirror/lang-less';
 import {markdown} from '@codemirror/lang-markdown';
 import {php} from '@codemirror/lang-php';
@@ -161,7 +161,7 @@
     case 'text/x-cmake':
       return StreamLanguage.define(cmake);
     case 'application/json':
-      return json();
+      return StreamLanguage.define(json);
     case 'text/x-cobol':
       return StreamLanguage.define(cobol);
     case 'text/x-coffeescript':