docs(angular): replace substr

Co-authored-by: Brandy Smith <[email protected]>

Author: thetaPC

docs/angular/your-first-app/7-live-reload.md

@@ -63,7 +63,7 @@ export class PhotoService {
     });
 
     // Delete photo file from filesystem
-    const filename = photo.filepath.substr(photo.filepath.lastIndexOf('/') + 1);
+    const filename = photo.filepath.slice(photo.filepath.lastIndexOf('/') + 1);
 
     await Filesystem.deleteFile({
       path: filename,

versioned_docs/version-v7/angular/your-first-app/7-live-reload.md

@@ -63,7 +63,7 @@ export class PhotoService {
     });
 
     // Delete photo file from filesystem
-    const filename = photo.filepath.substr(photo.filepath.lastIndexOf('/') + 1);
+    const filename = photo.filepath.slice(photo.filepath.lastIndexOf('/') + 1);
 
     await Filesystem.deleteFile({
       path: filename,