Fix #1986 | Aliases in use statements for stubs generartion

[AlexNDRmac]

Hello!

• Type: bug fix
• Link to issue: Alias in use statement not working in Stubs #1986

In raising this pull request, I confirm the following:

• I have checked that another pull request for this purpose does not exist
• I wrote some tests for this PR
• I updated the CHANGELOG

Small description of change:

• fixed stub generation for aliases in use statement
• small code refactoring
• added sharness test
• added unit tests

[codecov]

Codecov Report

Merging #1994 into development will increase coverage by 0.04%.
The diff coverage is 41.93%.

@@                Coverage Diff                @@
##             development    #1994      +/-   ##
=================================================
+ Coverage          34.25%   34.29%   +0.04%     
- Complexity          8156     8177      +21     
=================================================
  Files                561      561              
  Lines              45134    45196      +62     
=================================================
+ Hits               15462    15502      +40     
- Misses             29672    29694      +22

[sergeyklay]

Thank you