feat: show package's AUR link on error

[uwuclxdy]

This PR adds a helpful link to the package's AUR page on error.

before:

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==> ERROR: Integrity checks (sha256) differ in size from the source array.
error: failed to download sources for 'pince-0.5-1':
...

after:

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==> ERROR: Integrity checks (sha256) differ in size from the source array.
error: failed to download sources for 'pince-0.5-1': 
view on AUR: https://aur.archlinux.org/packages/pince
...