docs(wallet): fix misleading RBF comment in create_tx

[va-an]

Description

Closes: #45

Changelog notice

Fixed:

• Fix docs for Wallet:create_tx when empty output vector

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines
• I ran just p before pushing

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.04%. Comparing base (4e202c8) to head (62409a5).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #422   +/-   ##
=======================================
  Coverage   80.04%   80.04%           
=======================================
  Files          24       24           
  Lines        5336     5336           
  Branches      242      242           
=======================================
  Hits         4271     4271           
  Misses        987      987           
  Partials       78       78           

Flag	Coverage Δ
rust	80.04% <ø> (ø)

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