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:

• https://github.com/open-feature/openfeature.dev/pull/574
• https://github.com/open-feature/openfeature.dev/pull/573
• https://github.com/open-feature/openfeature.dev/pull/582

[sonarcloud[bot]]

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[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

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

Additional details and impacted files

```diff @@ 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](https://app.codecov.io/gh/open-feature/java-sdk/pull/964/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-feature) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/open-feature/java-sdk/pull/964/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-feature) | `95.26% <ø> (+0.22%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=open-feature#carryforward-flags-in-the-pull-request-comment) to find out more.

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