Make browser not supported messages translatable

src/locales/en.json

@@ -40,6 +40,14 @@
       "string": "Refresh",
       "context": "Button in some error messages that refreshes/reloads the page"
     },
+    "browserNotSupported": {
+      "string": "Browser not supported",
+      "description": "Message that appears when the user's browser does not support required features."
+    },
+    "browserNotSupportedDescription": {
+      "string": "Please update your browser.",
+      "description": "Additional text that appears when the user's browser does not support required features."
+    },
     "reportBug": {
       "string": "Report Bug"
     },

src/p4/P4.svelte

@@ -165,8 +165,8 @@
     <SelectProject bind:projectData />
   {:else}
     <Section accent="#4C97FF">
-      <h2>Browser not supported</h2>
-      <p>Please update your browser to use this site.</p>
+      <h2>{$_('p4.browserNotSupported')}</h2>
+      <p>{$_('p4.browserNotSupportedDescription')}</p>
     </Section>
   {/if}