fix debugging comments

src/utils/createDebuggingComment.ts

@@ -6,8 +6,8 @@ export default function createDebuggingComment(node: Node, generator: DomGenerat
 
 	let c = node.start;
 	if (node.type === 'ElseBlock') {
-		while (source[c] !== '{') c -= 1;
-		c -= 1;
+		while (source[c - 1] !== '{') c -= 1;
+		while (source[c - 1] === '{') c -= 1;
 	}
 
 	let d = node.expression ? node.expression.end : c;

test/js/samples/if-block-no-update/_actual-bundle-v2.js

@@ -244,7 +244,7 @@ function create_if_block(component, state) {
 	};
 }
 
-// (2:12)  {:else}
+// (3:0) {:else}
 function create_if_block_1(component, state) {
 	var p;
 

test/js/samples/if-block-no-update/expected-bundle-v2.js

@@ -222,7 +222,7 @@ function create_main_fragment(component, state) {
 	};
 }
 
-// (1:0) {{#if foo}}
+// (1:0) {#if foo}
 function create_if_block(component, state) {
 	var p;
 
@@ -244,7 +244,7 @@ function create_if_block(component, state) {
 	};
 }
 
-// (3:0) {{else}}
+// (3:0) {:else}
 function create_if_block_1(component, state) {
 	var p;