Mathsqrt (#3239)

* Output error when ls into a file without permission

* math sqrt

* added test to check fails when ls into prohibited dir

* fix lint

* math sqrt with tests and doc

* trigger wasm build

* Update filesystem_shell.rs

* always forgetting the linting

* fix clippy complaining

Co-authored-by: Jonathan Turner <jonathandturner@users.noreply.github.com>

crates/nu-command/tests/commands/math/mod.rs

@@ -2,6 +2,7 @@ mod avg;
 mod eval;
 mod median;
 mod round;
+mod sqrt;
 mod sum;
 
 use nu_test_support::{nu, pipeline};