Merge branch 'fix-code-suggestions-prompt-for-anthropic' into 'master'

Fix code generation anthropic prompt

Closes gitlab-org/modelops/applied-ml/code-suggestions/ai-assist#363

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/138637



Merged-by: Jan Provaznik <jprovaznik@gitlab.com>
Approved-by: Jan Provaznik <jprovaznik@gitlab.com>
Co-authored-by: Vitali Tatarintev <vtatarintev@gitlab.com>