Batch Changes Docs Updates for 6.4 (#1164)

<!-- Explain the changes introduced in your PR -->

## Pull Request approval

You will need to get your PR approved by at least one member of the
Sourcegraph team. For reviews of docs formatting, styles, and component
usage, please tag the docs team via the #docs Slack channel.

Author: MaedahBatool

README.md

@@ -2,7 +2,7 @@
 
 # Sourcegraph Docs
 
-<!-- Working branch for SG 6.4 Release -->
+<!-- Working branch for Sourcegraph 6.4 Release -->
 
 Welcome to the Sourcegraph documentation! We're excited to have you contribute to our docs. We've recently rearchitectured our docs tech stack — powered by Next.js, TailwindCSS and deployed on Vercel. This guide will walk you through the process of contributing to our documentation using the new tech stack.
 

docs/batch-changes/bulk-operations-on-changesets.mdx

@@ -37,6 +37,7 @@ Below is a list of supported bulk operations for changesets and the conditions w
 | **Close**                | Close the selected changesets on the code hosts                                                                                                                                                                                                                                                                                                                                                          |
 | **Publish**              | Publishes the selected changesets, provided they don't have a [`published` field](/batch-changes/batch-spec-yaml-reference#changesettemplatepublished) in the batch spec. You can choose between draft and normal changesets in the confirmation modal                                                                                                                                       |
 | **Export**              |  Export selected changesets that you can use for later use                                                                                                                                       |
+| **Re-execute**              |  Users can re-execute individual changeset creation logic for selected workspaces. This allows for creating new changesets for users who are using non-deterministic run steps (for example,LLMs)                                                                                                                                       |
 
 ## Monitoring bulk operations
 

docs/batch-changes/how-src-executes-a-batch-spec.mdx

@@ -23,6 +23,7 @@ Here, you will learn what happens when a user applies or previews a Batch Spec b
   - [Sending changeset specs](#sending-changeset-specs)
   - [Sending the batch spec](#sending-the-batch-spec)
   - [Preview or apply the batch spec](#preview-or-apply-the-batch-spec)
+    - [Halt execution](#halt-execution)
 
 The only difference is the last step, i.e., Preview or apply the batch spec. Here, the `src batch apply` command applies the batch spec, and the `src batch preview` prints a URL that gives you a preview of what would change if you applied the batch spec.
 
@@ -185,3 +186,7 @@ That request yields an ID uniquely identifying this expanded batch spec version.
 If `src batch apply` was used, then the ID of the batch change is used to send another request to the Sourcegraph instance to apply the batch spec.
 
 If `src batch preview` was used to execute and create the batch spec, then a URL is printed, pointing to a preview page on the Sourcegraph instance, on which you can see what would happen if you were to apply the batch spec.
+
+### Halt execution
+
+If you encounter an error while running the `src batch preview` command, there is a fail-fast mode that halts the batch change execution immediately. To implement this, you can add a `-fail-fast` flag to the `src batch preview` and `src batch apply` commands. Once added, your execution should immediately halt on the first error instead of continuing with other repositories. This streamlines the iteration loop for users building a batch change who want to identify errors quickly.