✨ Add Go language support

[arnoox]

Closes #76

Summary

Adds full Go language support to sphinx-codelinks, following the same patterns as existing language implementations (C++, Python, C#, Rust, YAML).

Changes

Core implementation

• pyproject.toml — add tree-sitter-go>=0.23.0 dependency
• source_discover/config.py — add go to CommentType enum and COMMENT_FILETYPE (.go files)
• config.py — add CommentType.go: ["//", "/*"] to COMMENT_MARKERS
• analyse/utils.py — add GO_QUERY, Go entry in SCOPE_NODE_TYPES (function_declaration, method_declaration, type_declaration, type_spec), and Go branch in init_tree_sitter()

Tests

• tests/test_analyse_utils.py — init_go_tree_sitter fixture + 11 tests covering comment extraction, find_associated_scope, find_next_scope, and find_enclosing_scope
• tests/doc_test/go_basic/ — minimal Sphinx integration project with a .go source file
• tests/test_src_trace.py — new parametrized case for go_basic + generated snapshot
• tests/test_source_discover.py / tests/test_src_trace.py — updated validation error messages to include "go" in the enum list

Documentation

• docs/source/components/analyse.rst — add Go to language support list
• docs/source/components/configuration.rst — add "go" to comment_type enum values and table
• docs/source/components/features.rst — add FE_GO feature block
• docs/source/development/change_log.rst — add changelog entry

Acceptance criteria

• Go parser / comment extractor added to sphinx-codelinks
• Unit tests covering Go comment annotation parsing (11 tests, all passing)
• Documentation updated to list Go as a supported language
• Integration test with a minimal Go project

[patdhlk]

LGTM - thanks for the PR