vxlan: Update documentation inside modifyvxlan-evpn.sh

[wido]

This commit does not change any functionality, it merely changes documentation inside the script.

The docs inside the script were incorrect and this PR fixes it. No functional changes.

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• Build/CI
• Test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 19.47%. Comparing base (8996286) to head (227c8c0).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main   #13584   +/-   ##
=========================================
  Coverage     19.47%   19.47%           
  Complexity    19352    19352           
=========================================
  Files          6294     6294           
  Lines        568164   568164           
  Branches      69600    69600           
=========================================
+ Hits         110664   110675   +11     
+ Misses       445422   445409   -13     
- Partials      12078    12080    +2     

Flag	Coverage Δ
uitests	3.44% <ø> (ø)
unittests	20.73% <ø> (+<0.01%)	⬆️

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[weizhouapache]

lgtm

[weizhouapache]

merging as this is minor doc change