Improve message when solving with incompatible environment/architecture combinations

[kratsg]

Problem description

In the case one defines this toml

[workspace]
authors = ["Giordon Stark <[email protected]>"]
channels = ["conda-forge"]
name = "debug"
platforms = ["osx-arm64", "linux-64"]
version = "0.1.0"

[tasks]

[dependencies]

and then runs something like

$ pixi add mod_wsgi
Error:   × failed to solve the conda requirements of 'default' 'osx-arm64'
  ╰─▶ Cannot solve the request because of: No candidates were found for mod_wsgi *.

This error message is a bit confusing for newcomers as one thinks of default and osx-arm64 on equal footing -- when in actuality one is an environment and one is a platform. A clearer error message might be more like

Error:   × failed to solve the conda requirements of environment 'default' for platform 'osx-arm64'

which at least clarifies the roles for each of those strings.

[ruben-arts]

Good idea! Would you be able to contribute this change?