tweak message

Author: Rich-Harris

packages/svelte/src/internal/client/proxy/readonly.js

@@ -44,7 +44,7 @@ export function readonly(value) {
 
 /** @returns {never} */
 const readonly_error = () => {
-	throw new Error(`Props are read-only, unless used with \`bind:\``);
+	throw new Error(`Props cannot be mutated, unless used with \`bind:\``);
 };
 
 /** @type {ProxyHandler<StateObject<any>>} */

packages/svelte/tests/runtime-runes/samples/proxy-prop-default-readonly/_config.js

@@ -14,5 +14,5 @@ export default test({
 		assert.htmlEqual(target.innerHTML, `<button>clicks: 0</button>`);
 	},
 
-	runtime_error: 'Props are read-only, unless used with `bind:`'
+	runtime_error: 'Props cannot be mutated, unless used with `bind:`'
 });

packages/svelte/tests/runtime-runes/samples/proxy-prop-readonly/_config.js

@@ -14,5 +14,5 @@ export default test({
 		assert.htmlEqual(target.innerHTML, `<button>clicks: 0</button>`);
 	},
 
-	runtime_error: 'Props are read-only, unless used with `bind:`'
+	runtime_error: 'Props cannot be mutated, unless used with `bind:`'
 });