How to find out "Problems in this file" errors in VS Code?

You can use this command:

Ctrl+Shift+M

By the way, you can quickly jump to errors and warnings in the project.

Cycle through errors with:

F8 or Shift+F8

You can filter problems either by type ('errors', 'warnings') or text matching with the above search bar you'll see.

Another useful filter is 'Show Active File Only'

Reference here

Bit late to the punch, however you can use the shortcut Ctrl + Shift + M, which will open the problems pane.