Fix "inside" broken with mixed quote types (#3109)

When two ambiguous delimiters (like single quotes) matched, the stack
truncation destroyed all entries above the match — including unrelated
delimiter types (backticks) pushed between the matched pair. Use splice
instead of truncation for ambiguous delimiters to preserve unrelated
stack entries.

Author: phillco

data/fixtures/recorded/surroundingPair/textual/changeInsideMixedQuotes.yml

@@ -0,0 +1,28 @@
+languageId: plaintext
+command:
+  version: 7
+  spokenForm: change inside pair
+  action:
+    name: clearAndSetSelection
+    target:
+      type: primitive
+      modifiers:
+        - {type: interiorOnly}
+        - type: containingScope
+          scopeType: {type: surroundingPair, delimiter: any}
+  usePrePhraseSnapshot: true
+initialState:
+  documentContents: |-
+    aaa's `bbb 'ccc'`
+    `ddd`
+  selections:
+    - anchor: {line: 1, character: 1}
+      active: {line: 1, character: 1}
+  marks: {}
+finalState:
+  documentContents: |-
+    aaa's `bbb 'ccc'`
+    ``
+  selections:
+    - anchor: {line: 1, character: 1}
+      active: {line: 1, character: 1}

packages/cursorless-engine/src/processTargets/modifiers/scopeHandlers/SurroundingPairScopeHandler/getSurroundingPairOccurrences.ts

@@ -43,8 +43,16 @@ export function getSurroundingPairOccurrences(
 
       const openingDelimiter = openingDelimitersStack[openingDelimiterIndex];
 
-      // Pop stack up to and including the opening delimiter
-      openingDelimitersStack.length = openingDelimiterIndex;
+      if (side === "unknown") {
+        // For ambiguous delimiters (eg quotes), remove only the matched
+        // entry so that unrelated delimiter types pushed between the
+        // matched pair are preserved.  See #3109.
+        openingDelimitersStack.splice(openingDelimiterIndex, 1);
+      } else {
+        // For non-ambiguous delimiters (eg parentheses), truncate the
+        // stack to enforce proper nesting.
+        openingDelimitersStack.length = openingDelimiterIndex;
+      }
 
       result.push({
         delimiterName: delimiterName,