Remove all associations with Brackets
Here's how to do it with any file (first method):


Highlight and right-click the file you want to change the default app for
Mouse over Open with... then click Other
Choose the desired application (i.e. Sublime) in the Choose Application prompt
Tick the checkbox Always Open With, then press Open (then close the application)


Alternatively:


Highlight and right-click the file you want to change the default app for
Select Get Info
Select Open with... in the window that just opened
Choose the desired application (from the drop-down list or Other)


If you are using Other, make sure to check Always Open With before pressing Add.

Ensure that the default application is displayed in the small box (as seen below, with Archive Utility)
Select Change All... to apply it to all files of the same type.