js: Normalize strings to double quotes.

Prettier would do this anyway, but it’s separated out for a more
reviewable diff.  Generated by ESLint.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

static/js/zulip.js

@@ -3,7 +3,7 @@
 // modules).  Please don't add things here.
 
 const home_msg_list = new message_list.MessageList({
-    table_name: 'zhome',
+    table_name: "zhome",
     filter: new Filter([{operator: "in", operand: "home"}]),
     muting_enabled: true,
 });