add dart class support (#2677)

## Checklist

- [x] I have added
[tests](https://www.cursorless.org/docs/contributing/test-case-recorder/)
- [x] I have updated the
[docs](https://github.com/cursorless-dev/cursorless/tree/main/docs) and
[cheatsheet](https://github.com/cursorless-dev/cursorless/tree/main/cursorless-talon/src/cheatsheet)
- [x] I have not broken the cheatsheet

---------

Co-authored-by: Pokey Rule <[email protected]>

Author: sonnyvesali

data/fixtures/scopes/dart/class.scope

@@ -0,0 +1,15 @@
+class MyClass {
+
+}
+---
+
+[Content] =
+[Removal] =
+[Domain] = 0:0-2:1
+  >---------------
+0| class MyClass {
+1|
+2| }
+   -<
+
+[Insertion delimiter] = "\n\n"

data/fixtures/scopes/dart/className.scope

@@ -0,0 +1,29 @@
+class MyClass {
+    
+}
+---
+
+[Content] = 0:6-0:13
+        >-------<
+0| class MyClass {
+
+[Removal] = 0:6-0:14
+        >--------<
+0| class MyClass {
+
+[Leading delimiter] = 0:5-0:6
+       >-<
+0| class MyClass {
+
+[Trailing delimiter] = 0:13-0:14
+               >-<
+0| class MyClass {
+
+[Domain] = 0:0-2:1
+  >---------------
+0| class MyClass {
+1|     
+2| }
+   -<
+
+[Insertion delimiter] = " "

data/playground/dart.dart

@@ -1,9 +1,22 @@
 foo() {
-  if (true) {}
+  final hi = '';
+  if (hi.isNotEmpty) {
+
+    //
+  }
+
+
+  else if (true) {
+    //
+  }
 
   final list = [1, 2, 3];
 
   final map = {
     'hi': 1,
   };
 }
+
+class Something{
+  
+}

packages/common/src/scopeSupportFacets/dart.ts

@@ -8,4 +8,6 @@ export const dartScopeSupport: LanguageScopeSupportFacetMap = {
   ifStatement: supported,
   list: supported,
   map: supported,
+  class: supported,
+  className: supported,
 };

queries/dart.scm

@@ -1,4 +1,3 @@
-
 ;;!! if () {}
 ;;!  ^^^^^^^^
 (if_statement) @ifStatement
@@ -16,3 +15,9 @@
   (set_or_map_literal)
   (map_pattern)
 ] @map
+
+;;!! class Foo {}
+;;!  ^^^^^^^^^^^^
+(class_definition
+  name: (_) @className
+) @class @className.domain