Allow source to accept paths with emojis (#3939)

* Allow sourcing paths with emojis

* Add source command tests for emoji paths

* Fmt

* Disable source tests on Windows with illegal paths

* Test sourcing also ASCII and single-quoted paths

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

@@ -52,6 +52,7 @@ mod select;
 mod semicolon;
 mod skip;
 mod sort_by;
+mod source;
 mod split_by;
 mod split_column;
 mod split_row;