emoji: Rename css_class to emoji_code in emoji.js.

Now that `emoji_collection` and `emojis_by_name` are global
datasources in the webapp we need to rename things carefully
to reflect their actual meaning. The fact that emoji code is
used as a css class for unicode emoji is one thing but it is
not its sole use so renaming it seems a good idea.

frontend_tests/node_tests/templates.js

@@ -693,7 +693,7 @@ run_test('emoji_popover_content', () => {
                         has_reacted: false,
                         is_realm_emoji: false,
                         name: '100',
-                        css_class: '100',
+                        emoji_code: '100',
                     },
                 ],
             },
@@ -733,13 +733,13 @@ run_test('emoji_popover_search_results', () => {
                 has_reacted: false,
                 is_realm_emoji: false,
                 name: 'test-1',
-                css_class: 'test-1',
+                emoji_code: 'test-1',
             },
             {
                 has_reacted: true,
                 is_realm_emoji: false,
                 name: 'test-2',
-                css_class: 'test-2',
+                emoji_code: 'test-2',
             },
         ],
     };
@@ -756,7 +756,7 @@ run_test('emoji_showcase', () => {
         emoji_dict: {
             name: "thumbs_up",
             is_realm_emoji: false,
-            css_class: "1f44d",
+            emoji_code: "1f44d",
             has_reacted: false,
         },
     };

static/js/emoji.js

@@ -100,7 +100,7 @@ exports.build_emoji_data = function (realm_emojis) {
                         name: emoji_name,
                         aliases: emoji.default_emoji_aliases[codepoint],
                         is_realm_emoji: false,
-                        css_class: codepoint,
+                        emoji_code: codepoint,
                         has_reacted: false,
                     };
                     exports.emojis_by_name[emoji_name] = emoji_dict;

static/templates/emoji_popover_emoji.handlebars

@@ -3,7 +3,7 @@
     {{#if is_realm_emoji}}
     <img src="{{url}}" class="emoji"/>
     {{else}}
-    <div class="emoji emoji-{{css_class}}"></div>
+    <div class="emoji emoji-{{emoji_code}}"></div>
     {{/if}}
 </div>
 {{/with}}

static/templates/emoji_showcase.handlebars

@@ -3,7 +3,7 @@
     {{#if is_realm_emoji}}
     <img src="{{url}}" class="emoji emoji-preview"/>
     {{else}}
-    <div class="emoji emoji-preview emoji-{{css_class}}"></div>
+    <div class="emoji emoji-preview emoji-{{emoji_code}}"></div>
     {{/if}}
     <div class="emoji-canonical-name" title="{{name}}">{{name}}</div>
 </div>