fix: update addTask method parameter type in API server documentation

- Changed the parameter type of the addTask method from TaskForm to Partial<Task> in the API server documentation for improved type flexibility.
- Ensured consistency across English, German, and French documentation files.

Author: geromegrignon

src/content/docs/de/api-server/create-task.mdx

@@ -60,7 +60,7 @@ This new **addTask** function defines the exchange with the API server:
    export class TaskService {
      private http = inject(HttpClient);
 
-     addTask(task: TaskForm) {
+     addTask(task:  Partial<Task>) {
        return this.http.post<Task>("http://localhost:3000/tasks", {
          ...task,
          createdAt: new Date(),

src/content/docs/en/api-server/create-task.mdx

@@ -60,7 +60,7 @@ This new **addTask** function defines the exchange with the API server:
    export class TaskService {
      private http = inject(HttpClient);
 
-     addTask(task: TaskForm) {
+     addTask(task:  Partial<Task>) {
        return this.http.post<Task>("http://localhost:3000/tasks", {
          ...task,
          createdAt: new Date(),

src/content/docs/fr/api-server/create-task.mdx

@@ -60,7 +60,7 @@ This new **addTask** function defines the exchange with the API server:
    export class TaskService {
      private http = inject(HttpClient);
 
-     addTask(task: TaskForm) {
+     addTask(task:  Partial<Task>) {
        return this.http.post<Task>("http://localhost:3000/tasks", {
          ...task,
          createdAt: new Date(),