fix activate.bat fail on windows

[NewUserHa]

version: micromamba-2.0.2-0.tar.bz2

curently run activate or activate.bat will end result with:

>> activate
>> micromamba activate
'micromamba' is not recognized as an internal or external command,
operable program or batch file.

the reason is DOSKEY "cannot run a macro from a command that you didn't type in manually" confirmed in docs and other sources eg https://stackoverflow.com/questions/71229141/windows-bat-file-using-start-cmd-k-with-doskey-not-work

this PR fixed it.

[JohanMabille]

Thanks for your PR. However, I don't understand how this fixes the issue:

• exe_name.string() returns a string (mamba or micromamba, depending on the executable taht runs shell init) that is inserted in the generate bat file, so in the end the doskey contains a string with the exe name (not an alias or anything else).
• except on CI where Autorun is specically disabled, micromamba activate works once the shell init has be done (and if micromamba.exe is in th path).

Am I missing something here?

[NewUserHa]

the current activate.bat will not work
because after .bat files got generated even there is a DOSKEY micromamba=... in mamba_hook.bat and a fresh cmd called it,
when run activate.bat and the line micromamba activate %* of activate.bat execute, it will error by 'micromamba' is not recognized as an internal or external command, operable program or batch file.,
so this PR updated micromamba(from exe_name.string()) to use mamba(underhood mamba.bat in env) instead, because Macro set by DOSKEY only works in interactive

[JohanMabille]

Got it! Actually we cannnot hardcode that name to mamba, because there are configuration where we expect a micromamba.bat file (and the mamba.bat will not exist). There is an on-going work in #3546 which should fix it for every use case (mamba / micromamba).