fix: correct spelling errors in test files (#17630)

Fix "wich" -> "which", "aswell" -> "as well" in CSS global-block test,
and "occurence" -> "occurrence" in sourcemaps test type definition.

packages/svelte/tests/css/samples/global-block/expected.css

@@ -39,7 +39,7 @@
 		/*}*/
 	}
 
-	/* ...wich is equivalent to `div :global { &.x { ...} }` ... */
+	/* ...which is equivalent to `div :global { &.x { ...} }` ... */
 	div.svelte-xyz {
 		&.x {
 			color: green;

packages/svelte/tests/css/samples/global-block/input.svelte

@@ -41,7 +41,7 @@
 		}
 	}
 
-	/* ...wich is equivalent to `div :global { &.x { ...} }` ... */
+	/* ...which is equivalent to `div :global { &.x { ...} }` ... */
 	div :global {
 		&.x {
 			color: green;

packages/svelte/tests/sourcemaps/test.ts

@@ -8,9 +8,9 @@ import { decode } from '@jridgewell/sourcemap-codec';
 type SourceMapEntry =
 	| string
 	| {
-			/** If not the first occurence, but the nth should be found */
+			/** If not the first occurrence, but the nth should be found */
 			idxOriginal?: number;
-			/** If not the first occurence, but the nth should be found */
+			/** If not the first occurrence, but the nth should be found */
 			idxGenerated?: number;
 			/** The original string to find */
 			str: string;