update tests

Author: Rich-Harris

packages/svelte/tests/compiler-errors/samples/css-global-block-declaration/_config.js

@@ -3,7 +3,7 @@ import { test } from '../../test';
 export default test({
 	error: {
 		code: 'css_global_block_invalid_declaration',
-		message: 'A `:global {...}` block can only contain rules, not declarations',
+		message: 'A top-level `:global {...}` block can only contain rules, not declarations',
 		position: [109, 119]
 	}
 });

packages/svelte/tests/compiler-errors/samples/css-global-modifier-start-1/_config.js

@@ -3,7 +3,7 @@ import { test } from '../../test';
 export default test({
 	error: {
 		code: 'css_global_block_invalid_modifier_start',
-		message: 'A `:global` selector at the very beginning cannot be modified by other selectors',
+		message: 'A `:global` selector can only be modified if it is a descendant of other selectors',
 		position: [75, 77]
 	}
 });

packages/svelte/tests/compiler-errors/samples/css-global-modifier-start-2/_config.js

@@ -3,7 +3,7 @@ import { test } from '../../test';
 export default test({
 	error: {
 		code: 'css_global_block_invalid_modifier_start',
-		message: 'A `:global` selector at the very beginning cannot be modified by other selectors',
+		message: 'A `:global` selector can only be modified if it is a descendant of other selectors',
 		position: [147, 148]
 	}
 });

packages/svelte/tests/validator/samples/css-invalid-type-selector-placement/errors.json

@@ -1,7 +1,7 @@
 [
 	{
 		"code": "css_type_selector_invalid_placement",
-		"message": "`:global(...)` must not be followed with a type selector",
+		"message": "`:global(...)` must not be followed by a type selector",
 		"start": {
 			"line": 17,
 			"column": 14