Fix tab expansion for non-ASCII file paths

[dahlbyk]

Fix #64 now that #359 and #397 have fixed the encoding issue I encountered at the time.

cc @haacked

[rkeithhill]

Don't forget to add this to the CHANGELOG.md. :-)

[dahlbyk]

Don't forget to add this to the CHANGELOG.md. :-)

Do I fail at reading comprehension, or does CHANGELOG (even after #402) not mention the other encoding fixes either? Regardless, to avoid conflicts I'll add a note about this to #402 after this gets merged.

[dahlbyk]

@rkeithhill do you think we would be able to reasonably test this particularly quote/encoding round-trip?

[rkeithhill]

Do I fail at reading comprehension, or does CHANGELOG (even after #402) not mention the other encoding fixes either

I suspect not. ;-) I added stuff I found but no guarantees that I found everything.

do you think we would be able to reasonably test this particularly quote/encoding round-trip?

Not sure. Would have to experiment with it.

[dahlbyk]

Figured out a failing test that is made to pass:

   Context Add/Reset/Checkout TabExpansion Tests
    [-] Tab completes non-ASCII file name 782ms
      at <ScriptBlock>, C:\Dev\OSS\posh-git\test\TabExpansion.Tests.ps1: line 144
      Expected string length 12 but was 25. Strings differ at index 0.
      Expected: {posh�git.txt}
      But was:  {"posh\342\200\242git.txt"}
      -----------^
      144:             $result | Should BeExactly 'posh�git.txt'

Oddly, VS Code is showing Expected: {poshgit.txt} (i.e the UTF-8 bullet is invisble) when it should be Expected: {posh•git.txt}, but it seems to work. ¯\_(ツ)_/¯

[rkeithhill]

Cool! LGTM.