chore: simplify updates (#10922)

* remove if blocks around attribute updates

* remove singular updates

* simplify

* get rid of text_effect

* get rid of class_toggle_effect and style_effect

* remove spread_attributes_effect

* simplify

* simplify

* simplify

* remove unused stuff

* get rid of spread_dynamic_element_attributes_effect

* remove set_custom_element_data_effect

* unused import

* more descriptive names

Author: Rich-Harris

packages/svelte/src/compiler/phases/3-transform/client/types.d.ts

@@ -32,12 +32,7 @@ export interface ComponentClientTransformState extends ClientTransformState {
 	/** Stuff that happens before the render effect(s) */
 	readonly init: Statement[];
 	/** Stuff that happens inside the render effect */
-	readonly update: {
-		/** If the update array only contains a single entry, this singular entry will be used, if present */
-		singular?: Statement;
-		/** Used if condition for singular prop is false (see comment above) */
-		grouped: Statement;
-	}[];
+	readonly update: Statement[];
 	/** Stuff that happens after the render effect (control blocks, dynamic elements, bindings, actions, etc) */
 	readonly after_update: Statement[];
 	/** The HTML template string */