goal: minor text fix

[nullun]

-t doesn't exist for goal clerk multisig signprogram and the text was probably copied from addSigCmd

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 50.47%. Comparing base (e11f501) to head (88fa0a8).
⚠️ Report is 3 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6404      +/-   ##
==========================================
- Coverage   50.66%   50.47%   -0.19%     
==========================================
  Files         661      654       -7     
  Lines      110781   110683      -98     
==========================================
- Hits        56122    55868     -254     
- Misses      51793    51939     +146     
- Partials     2866     2876      +10     

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