docs: remove golang snippet and fix variable name

[beeme1mr]

This PR

• removes Go related snippet on the readme
• fixes example variable name on the readme

Notes

This addresses issues opened in the docs repo:

• Remove golang-related note from Java SDK docs openfeature.dev#574
• Fix variable name in a code snippet openfeature.dev#573
• doc(technologies.server.java): use proper variable openfeature.dev#582

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.26%. Comparing base (b3ba6fe) to head (65d8bf0).

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #964      +/-   ##
============================================
+ Coverage     95.03%   95.26%   +0.22%     
- Complexity      391      392       +1     
============================================
  Files            37       37              
  Lines           887      887              
  Branches         54       54              
============================================
+ Hits            843      845       +2     
+ Misses           24       23       -1     
+ Partials         20       19       -1     

Flag	Coverage Δ
unittests	95.26% <ø> (+0.22%)	⬆️

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