[chore][githubgen] Remove unnecessary trailing whitespace

[crobert-1]

Context in open-telemetry/opentelemetry-collector-contrib#37292

Currently, lines generated for unmaintained components in .github/CODEOWNERS have a trailing whitespace. This is a whitespace error. This removes the trailing whitespace.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 48.89%. Comparing base (c77c83e) to head (10e233e).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
githubgen/codeowners.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #663   +/-   ##
=======================================
  Coverage   48.89%   48.89%           
=======================================
  Files          57       57           
  Lines        3383     3383           
=======================================
  Hits         1654     1654           
  Misses       1568     1568           
  Partials      161      161           

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