Log Message:
shells/nushell: update to 0.81.0

Themes of this release / New features
Polishing the experience
 This release focuses on improving the user experience, fixing some
 long-standing bugs, and adding a few helpful features.

 One of the bugs that was fixed for 0.81 was a long-standing issue with
 reedline, Nushell's line editor. Now, Nushell will prefer to move to make room
 for text that had been output rather than risking writing over top of it.
 This maybe improve the general experience of working in the terminal,
 resizing, and more.

 There have also been fixes to table printing to make it work better for more
 cases.

 Startup time improvements

 Startup times have also been improved. Through a combination of various fixes
 to both how the standard library files were handles and how the parser worked,
 we've been able to see significant improvements, sometimes as high as
 30-50% faster.

Breaking changes
 We had to remove ARMv7 and RISC-V from this release due to a breaking change
 in one of the dependencies. We hope to resolve this for future releases.

 Exclude globs now need square brackets

 view source now works over rest arguments

 alias calls are now position dependent