docs: update buy-direct example

[dpdanpittman]

Description

Closes: #XXXX

Updates the buy-direct example in marketplace/client/tx.go. In the current example disable-auto-retire is set to true but a retirement reason is given. Setting disable-auto-retire to true does not auto retire credits so a retirement reason is not needed. This update changes the true value to false to coincide with the --retirement-reason flag usage.

---

Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.

I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[codecov]

Codecov Report

Merging #1784 (9fa554e) into main (0c2af34) will not change coverage.
The diff coverage is 100.00%.

❗ Current head 9fa554e differs from pull request most recent head 05aa568. Consider uploading reports for the commit 05aa568 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1784   +/-   ##
=======================================
  Coverage   73.00%   73.00%           
=======================================
  Files         228      228           
  Lines       13577    13577           
=======================================
  Hits         9912     9912           
  Misses       2934     2934           
  Partials      731      731           

Impacted Files	Coverage Δ
x/ecocredit/marketplace/client/tx.go	86.07% <100.00%> (ø)