Fix towncrier entry point after module refactoring

Update entry point from old module name:
- vcs_versioning._version_schemes_towncrier
to new package path:
- vcs_versioning._version_schemes._towncrier

Also update documentation references in RELEASE_SYSTEM.md and CONTRIBUTING.md

Author: RonnyPfannschmidt

CONTRIBUTING.md

@@ -137,7 +137,7 @@ The release system is designed to be reusable by other projects:
 
 ### Key Components
 
-1. **Version Scheme** (`vcs_versioning._version_schemes_towncrier`)
+1. **Version Scheme** (`vcs_versioning._version_schemes._towncrier`)
    - Analyzes fragments to determine version bump
    - Used by both development builds and release workflow
    - No version calculation logic in scripts - single source of truth

RELEASE_SYSTEM.md

@@ -16,7 +16,7 @@ Fragment types determine version bumps:
 - `feature`, `deprecation` → minor bump
 - `bugfix`, `doc`, `misc` → patch bump
 
-Entry point: `vcs_versioning._version_schemes_towncrier:version_from_fragments`
+Entry point: `vcs_versioning._version_schemes._towncrier:version_from_fragments`
 
 Tests: `vcs-versioning/testing_vcs/test_version_scheme_towncrier.py`
 

vcs-versioning/pyproject.toml

@@ -75,7 +75,7 @@ node-and-timestamp = "vcs_versioning._version_schemes:get_local_node_and_timesta
 "post-release" = "vcs_versioning._version_schemes:postrelease_version"
 "python-simplified-semver" = "vcs_versioning._version_schemes:simplified_semver_version"
 "release-branch-semver" = "vcs_versioning._version_schemes:release_branch_semver_version"
-"towncrier-fragments" = "vcs_versioning._version_schemes_towncrier:version_from_fragments"
+"towncrier-fragments" = "vcs_versioning._version_schemes._towncrier:version_from_fragments"
 
 [tool.hatch.version]
 source = "code"