Add item scope to JS (#2675)

```js
const value = [1, 2];
```
This example is problematic. Currently we test the language specific
implementation before the text based one. This means that if your cursor
is inside the curly brackets `item` is `value = [1, 2]`. I don't think
this can be solved until we have a better `oneOf` implementation of
collection item.
Same problem with Java
#2674

To fix that above I made a change so that the text based item can be
used even if there is a syntax tree one available if it's smaller. This
needs to merge before the java pr.

## Checklist

- [x] I have added
[tests](https://www.cursorless.org/docs/contributing/test-case-recorder/)
- [/] 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)
- [/] I have not broken the cheatsheet

Author: AndreasArvidsson

data/fixtures/recorded/languages/typescript/takeItem.yml

@@ -23,5 +23,5 @@ finalState:
 
     const value = { a: 1, b: 2, c: 3 };
   selections:
-    - anchor: {line: 1, character: 0}
-      active: {line: 1, character: 35}
+    - anchor: {line: 1, character: 6}
+      active: {line: 1, character: 34}

data/fixtures/scopes/javascript.core/collectionItem.unenclosed.scope

@@ -0,0 +1,33 @@
+let foo, bar;
+---
+
+[#1 Content] =
+[#1 Domain] = 0:4-0:7
+      >---<
+0| let foo, bar;
+
+[#1 Removal] = 0:4-0:9
+      >-----<
+0| let foo, bar;
+
+[#1 Trailing delimiter] = 0:7-0:9
+         >--<
+0| let foo, bar;
+
+[#1 Insertion delimiter] = ", "
+
+
+[#2 Content] =
+[#2 Domain] = 0:9-0:12
+           >---<
+0| let foo, bar;
+
+[#2 Removal] = 0:7-0:12
+         >-----<
+0| let foo, bar;
+
+[#2 Leading delimiter] = 0:7-0:9
+         >--<
+0| let foo, bar;
+
+[#2 Insertion delimiter] = ", "

packages/common/src/scopeSupportFacets/javascript.ts

@@ -112,6 +112,8 @@ export const javascriptCoreScopeSupport: LanguageScopeSupportFacetMap = {
   "value.return": supported,
   "value.return.lambda": supported,
   "value.field": supported,
+
+  "collectionItem.unenclosed": supported,
 };
 
 export const javascriptJsxScopeSupport: LanguageScopeSupportFacetMap = {

packages/cursorless-engine/src/processTargets/modifiers/ContainingScopeStage.ts

@@ -45,23 +45,39 @@ export class ContainingScopeStage implements ModifierStage {
         .run(target);
     }
 
-    const containingScope = getContainingScopeTarget(
+    const containingScopes = getContainingScopeTarget(
       target,
       scopeHandler,
       ancestorIndex,
     );
-
-    if (containingScope == null) {
-      if (scopeType.type === "collectionItem") {
-        // For `collectionItem`, fall back to generic implementation
-        return this.modifierStageFactory
+    if (scopeType.type === "collectionItem") {
+      // For `collectionItem`, combine with generic implementation
+      try {
+        const legacyScopes = this.modifierStageFactory
           .getLegacyScopeStage(this.modifier)
           .run(target);
+        if (containingScopes == null) {
+          return legacyScopes;
+        }
+        if (containingScopes.length === 1 && legacyScopes.length === 1) {
+          const containingRange = containingScopes[0].contentRange;
+          const legacyRange = legacyScopes[0].contentRange;
+          if (
+            containingRange.contains(legacyRange) &&
+            !containingRange.isRangeEqual(legacyRange)
+          ) {
+            return legacyScopes;
+          }
+        }
+      } catch (_ex) {
+        // Do nothing
       }
+    }
 
+    if (containingScopes == null) {
       throw new NoContainingScopeError(this.modifier.scopeType.type);
     }
 
-    return containingScope;
+    return containingScopes;
   }
 }

queries/javascript.core.scm

@@ -272,6 +272,19 @@
   (#has-multiple-children-of-type? @_dummy variable_declarator)
 )
 
+;;!! let foo, bar;
+;;!      ^^^  ^^^
+(
+  (lexical_declaration
+    (variable_declarator)? @_.leading.endOf
+    .
+    (variable_declarator) @collectionItem
+    .
+    (variable_declarator)? @_.trailing.startOf
+  )
+  (#insertion-delimiter! @collectionItem ", ")
+)
+
 (expression_statement
   [
     ;; name: