Shortcut for brush/pencil/spray drawing size

[Kuchasz]

Is your feature request related to a problem? Please describe.
As a long-term photoshop user i often use its option to change brush size with the keyboard shortcuts. Having to switch the context just to change brush size drives me crazy.

Describe the solution you'd like
Id like to change brush/pencil/spray size with the keyboard keys: [ and ]. Probably some software like MS Paint does the same thing with + and -