Correct the rule description

[0x6675636b796f75676974687562]

What's done:

• Originally, the description of the KDOC_CONTAINS_DATE_OR_AUTHOR has had the
  reverse meaning. Now it's correct.

[codecov]

Codecov Report

Merging #1467 (3eafe23) into master (ff346b0) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #1467      +/-   ##
============================================
+ Coverage     83.30%   83.33%   +0.02%     
- Complexity     2561     2562       +1     
============================================
  Files           107      107              
  Lines          7607     7614       +7     
  Branches       2100     2100              
============================================
+ Hits           6337     6345       +8     
  Misses          384      384              
+ Partials        886      885       -1     

Flag	Coverage Δ
unittests	83.33% <100.00%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...tlin/org/cqfn/diktat/ruleset/constants/Warnings.kt	98.08% <100.00%> (ø)
...ktat/ruleset/rules/chapter2/kdoc/KdocFormatting.kt	85.06% <100.00%> (+0.95%)	⬆️

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[github-actions]

JUnit Tests (macOS, EnricoMi/publish-unit-test-result-action@v1)

1 288 tests   1 272 ✔️  1m 11s ⏱️
   159 suites       16 💤
   159 files           0 ❌

Results for commit 359a864.

[github-actions]

JUnit Tests (Windows, EnricoMi/publish-unit-test-result-action@v1)

1 302 tests   1 287 ✔️  2m 33s ⏱️
   160 suites       15 💤
   160 files           0 ❌

Results for commit 359a864.