feat: changed green "Done" button to read "Mark task done" (#1340)

The green button can be confusing because the wording "Done" can be interpreted as "done editing the task" or "the task should be marked as done". Changing the text in the button makes the description more precise.

Co-authored-by: David Morlitz <david@morlitz.com>
Reviewed-on: https://kolaente.dev/vikunja/frontend/pulls/1340
Reviewed-by: konrad <k@knt.li>
Co-authored-by: dmorlitz <david@morlitz.com>
Co-committed-by: dmorlitz <david@morlitz.com>

cypress/integration/task/task.spec.js

@@ -128,7 +128,7 @@ describe('Task', () => {
 			cy.visit(`/tasks/${tasks[0].id}`)
 
 			cy.get('.task-view .action-buttons .button')
-				.contains('Done!')
+				.contains('Mark task done!')
 				.click()
 
 			cy.get('.task-view .heading .is-done')

src/i18n/lang/en.json

@@ -545,7 +545,7 @@
       "chooseStartDate": "Click here to set a start date",
       "chooseEndDate": "Click here to set an end date",
       "move": "Move task to a different list",
-      "done": "Done!",
+      "done": "Mark task done!",
       "undone": "Mark as undone",
       "created": "Created {0} by {1}",
       "updated": "Updated {0}",
@@ -781,7 +781,7 @@
     "then": "then",
     "task": {
       "title": "Task Page",
-      "done": "Mark a task as done",
+      "done": "Done",
       "assign": "Assign to a user",
       "labels": "Add labels to this task",
       "dueDate": "Change the due date of this task",