Added additional sentence to custom args hint and fixed issue where empty args could be added through the args modifier

src/app/dialogs/arg-modifier-dialog/arg-modifier-dialog.component.ts

@@ -161,6 +161,11 @@ export class ArgModifierDialogComponent implements OnInit, AfterViewInit {
   add(event) {
     const input = event.input;
     const arg = event.value;
+
+    if (!arg || arg.trim().length === 0) {
+      return;
+    }
+
     this.args_array.push(arg);
     if (this.modified_args.length > 0) {
       this.modified_args += ',,'

src/app/download-item/download-item.component.html

@@ -24,7 +24,7 @@
             </div>
         </mat-expansion-panel-header>
         <div *ngIf="download.error">
-            <strong><ng-container i18n="Error label">An error has occured:</ng-container></strong>
+            <strong><ng-container i18n="Error label">An error has occurred:</ng-container></strong>
             <br/>
             {{download.error}}
         </div>

src/app/main/main.component.html

@@ -116,7 +116,7 @@
                             <input [(ngModel)]="customArgs" [ngModelOptions]="{standalone: true}" [disabled]="!customArgsEnabled" matInput placeholder="Custom args" i18n-placeholder="Custom args placeholder">
                             <mat-hint>
                                 <ng-container i18n="Custom Args input hint">
-                                    No need to include URL, just everything after.
+                                    No need to include URL, just everything after. Args are delimited using two commas like so: ,,
                                 </ng-container>
                             </mat-hint>
                         </mat-form-field>

src/app/settings/settings.component.html

@@ -143,7 +143,7 @@
                     <div class="col-12 mt-5">
                         <mat-form-field class="text-field" style="margin-right: 12px;" color="accent">
                             <textarea matInput [(ngModel)]="new_config['Downloader']['custom_args']" placeholder="Custom args" i18n-placeholder="Custom args input placeholder"></textarea>
-                            <mat-hint><ng-container i18n="Custom args setting input hint">Global custom args for downloads on the home page.</ng-container></mat-hint>
+                            <mat-hint><ng-container i18n="Custom args setting input hint">Global custom args for downloads on the home page. Args are delimited using two commas like so: ,,</ng-container></mat-hint>
                             <button class="args-edit-button" (click)="openArgsModifierDialog()" mat-icon-button><mat-icon>edit</mat-icon></button>
                         </mat-form-field>
                     </div>