Fix compatiblity of methods with native return type in PHP 8.1

[SilinMykola]

This pull request (PR) provides fixes for the extension to make it compatible with PHP 8.1.
The fixes provides backward compatibility with previous versions PHP.

Return types have been fixed using attribute #[\ReturnTypeWillChange], please see this link

[codecov]

Codecov Report

Merging #1011 (efe46aa) into master (2bac02f) will decrease coverage by 0.01%.
The diff coverage is 33.33%.

@@             Coverage Diff              @@
##             master    #1011      +/-   ##
============================================
- Coverage     94.49%   94.47%   -0.02%     
- Complexity       50       53       +3     
============================================
  Files           120      120              
  Lines          9634     9637       +3     
============================================
+ Hits           9104     9105       +1     
- Misses          530      532       +2     

Impacted Files	Coverage Δ
src/Error/Error.php	94.00% <0.00%> (-0.95%)	⬇️
src/Language/SourceLocation.php	75.00% <0.00%> (-6.82%)	⬇️
src/Type/Definition/Type.php	97.89% <100.00%> (+0.02%)	⬆️

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[spawnia]

Thanks, fixed and backported to v14