Add status code in prefix

Fixes #125.

package.json

@@ -1,6 +1,6 @@
 {
     "name": "fwdekker.com",
-    "version": "0.33.10",
+    "version": "0.34.0",
     "description": "The source code of [my personal website](https://fwdekker.com/).",
     "author": "Felix W. Dekker",
     "browser": "dist/bundle.js",

src/main/css/main.css

@@ -102,3 +102,8 @@ body {
 #terminalSuggestions {
     display: block;
 }
+
+
+.errorMessage {
+    color: red;
+}

src/main/js/Shell.ts

@@ -110,7 +110,10 @@ export class Shell {
             .map(part => new Directory().nameString(part.fileName, part))
             .join("/");
 
-        return `${userName}@fwdekker.com <span class="prefixPath">${rootText}${partText}</span>&gt; `;
+        const status = this.environment.get("status");
+        const statusString = status === "0" ? "" : ` <span class="errorMessage">[${status}]</span>`;
+
+        return `${userName}@fwdekker.com <span class="prefixPath">${rootText}${partText}</span>${statusString}&gt; `;
     }