Multiline scripts part 2 (#2795)

* Begin allowing comments and multiline scripts.

* clippy

* Finish moving to groups. Test pass

* Keep going

* WIP

* WIP

* BROKEN WIP

* WIP

* WIP

* Fix more tests

* WIP: alias starts working

* Broken WIP

* Broken WIP

* Variables begin to work

* captures start working

* A little better but needs fixed scope

* Shorthand env setting

* Update main merge

* Broken WIP

* WIP

* custom command parsing

* Custom commands start working

* Fix coloring and parsing of block

* Almost there

* Add some tests

* Add more param types

* Bump version

* Fix benchmark

* Fix stuff

crates/nu-protocol/src/signature.rs

@@ -118,6 +118,18 @@ pub struct Signature {
     pub is_filter: bool,
 }
 
+impl PartialEq for Signature {
+    fn eq(&self, other: &Self) -> bool {
+        self.name == other.name
+            && self.usage == other.usage
+            && self.positional == other.positional
+            && self.rest_positional == other.rest_positional
+            && self.is_filter == other.is_filter
+    }
+}
+
+impl Eq for Signature {}
+
 impl Signature {
     pub fn shift_positional(&mut self) {
         self.positional = Vec::from(&self.positional[1..]);