Small fix in deleteAll documentation regardning namespaces (#314)

## Problem

Describe the purpose of this change. What problem is being solved and
why?
Was confusing when I read the commented documentation.

## Solution

[Describe the approach you took. Link to any relevant bugs, issues,
docs, or other
resources.](https://docs.pinecone.io/guides/data/delete-data#delete-all-records-from-a-namespace)
Change documentation to represent to default namespace being deleted.

## Type of Change

- [ ] Non-code change (docs, etc)


## Test Plan

Describe specific steps for validating this change.

---------

Co-authored-by: Audrey Sage Lorberfeld <[email protected]>

src/data/index.ts

@@ -268,7 +268,8 @@ export class Index<T extends RecordMetadata = RecordMetadata> {
    *
    * await index.deleteAll();
    *
-   * // Records from namespace 'foo' are now deleted. Records in other namespaces are not modified.
+   * // Records from the default namespace '' are now deleted. Records in other namespaces are not modified.
+   *
    * await index.describeIndexStats();
    * // {
    * //  namespaces: {
@@ -278,10 +279,6 @@ export class Index<T extends RecordMetadata = RecordMetadata> {
    * //   indexFullness: 0,
    * //   totalRecordCount: 1
    * // }
-   *
-   * await index.deleteAll();
-   * // Since no namespace was specified, records in default namespace '' are now deleted.
-   *
    * ```
    * @throws {@link Errors.PineconeConnectionError} when network problems or an outage of Pinecone's APIs prevent the request from being completed.
    * @returns A promise that resolves when the delete is completed.