fix: fix incorrect winget install cmd

[rmoraes92]

the previous version of the recommended command line was throwing an error.

this new proposed one will actually install the correct nushell from the winget store.

[fdncred]

why is it necessary to use --source winget?

[rmoraes92]

Hi @fdncred

I've tried to install if without the --source but it throws the following (roughly translated from pt-BR):

Failed to search the source: msstore
An unexpected error occurred while executing the command:
0x8a15005e: The server's certificate didn't match any of the expected values.

The following packages were found among the working sources. Specify one of them using the --source option to continue. 

Name ID              Source
nu   Nushell.Nushell winget

The only way I was able to resolve this was passing the --source.

I not a Windows-savvy (much less a winget one) person but this might be an issue related to how my sources are currently setup.

Here the output for winget source list

Named Argument                                    Explicit
---------------------------------------------------------------
msstore https://storeedgefd.dsx.mp.microsoft.com/v9.0 false
winget  https://cdn.winget.microsoft.com/cache        false

If so, I don't think it would hurt to add the --source parameter in the documentation as an ensurance that the command will work no matter how many source the person has. Right?

[fdncred]

winget install nu seems to work for me. My source list is the same as yours.