[FIX] Corpus - extend attributes: Fix error with renamed text feature

[PrimozGodec]

Issue

When in extednd_attributes function one of the text features is renamed extending fails with ValueError.

Description of changes

Changed set_text_features function to handle cases with renamed features (when the feature has Identity in compute_values).

Includes

• Code changes
• Tests
• Documentation

[codecov-commenter]

Codecov Report

Merging #574 into master will increase coverage by 3.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #574      +/-   ##
==========================================
+ Coverage   70.86%   73.90%   +3.03%     
==========================================
  Files          66       66              
  Lines        7565     7575      +10     
  Branches      999     1002       +3     
==========================================
+ Hits         5361     5598     +237     
+ Misses       2011     1767     -244     
- Partials      193      210      +17