fix: Fix console error when 'Toggle task done' deletes the line

Fixes #3256

Author: claremacrae

src/Commands/ToggleDone.ts

@@ -75,7 +75,7 @@ export const toggleLine = (line: string, path: string): EditorInsertion => {
     });
     if (task !== null) {
         const lines = task.toggleWithRecurrenceInUsersOrder().map((t) => t.toFileLineString());
-        const newLineNumber = lines.length - 1;
+        const newLineNumber = lines.length > 0 ? lines.length - 1 : 0;
         return { text: lines.join('\n'), moveTo: { line: newLineNumber } };
     } else {
         // If the task is null this means that we have one of:

tests/Commands/ToggleDone.test.ts

@@ -183,7 +183,7 @@ describe('ToggleDone', () => {
     });
 
     describe('on completion', () => {
-        it.failing('should delete a self-deleting task - cursor at start of line', () => {
+        it('should delete a self-deleting task - cursor at start of line', () => {
             // Issue #3256 - traceback occurred.
             testToggleLine(
                 // Force linebreak
@@ -192,7 +192,7 @@ describe('ToggleDone', () => {
             );
         });
 
-        it.failing('should delete a self-deleting task - cursor at end of line', () => {
+        it('should delete a self-deleting task - cursor at end of line', () => {
             // Issue #3256 - traceback occurred.
             testToggleLine(
                 // Force linebreak