Wish I had come across this during my PuTTY days!
The TL;DR summary is that by default PuTTY uses an ASCII encoding while most Linux and other OSes uses UTF-8 encoding. It’s because of this mismatch that manpages and such sometimes appear with â characters. Change the PuTTY encoding and find happiness!
[Aside] Improving your PuTTY connections by rakhesh is licensed under a Creative Commons Attribution 4.0 International License.