Docs: improve comments, error checking and defaults

src/Models/ThemeConfig/Conversion/PrepareTheme.ts

@@ -535,7 +535,7 @@ export class PrepareTheme extends Fuse<LayoutConfigJson> {
             new SetDefault("socialImage", "assets/SocialImage.png", true),
             // We expand all tagrenderings first...
             new On("layers", new Each(new PrepareLayer(state))),
-            // Then we apply the override all
+            // Then we apply the override all. We must first expand everything in case that we override something in an expanded tag
             new ApplyOverrideAll(),
             // And then we prepare all the layers _again_ in case that an override all contained unexpanded tagrenderings!
             new On("layers", new Each(new PrepareLayer(state))),

src/Models/ThemeConfig/Conversion/Validation.ts

@@ -882,6 +882,10 @@ class MiscTagRenderingChecks extends DesugaringStep<TagRenderingConfigJson> {
                 )
         }
 
+        if(json.icon?.["size"]){
+            context.enters("icon","size").err("size is not a valid attribute. Did you mean 'class'? Class can be one of `small`, `medium` or `large`")
+        }
+
         if (json.freeform) {
             if (json.render === undefined) {
                 context

src/Models/ThemeConfig/TagRenderingConfig.ts

@@ -153,7 +153,7 @@ export default class TagRenderingConfig {
             this.renderIconClass = "small"
         } else if (typeof json.icon === "object") {
             this.renderIcon = json.icon.path
-            this.renderIconClass = json.icon.class
+            this.renderIconClass = json.icon.class ?? "small"
         }
         this.metacondition = TagUtils.Tag(
             json.metacondition ?? { and: [] },