Size checks print out target firmware file instead

[tzarc]

Description

There's been a few instances of people trying to flash the hex file listed during size checks, rather than the output firmware in the root directory. This is problematic for ARM builds, as they'll generally be in BIN format -- the output still lists the HEX path.

Old:

New:

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).