Fix Registry Warning Message and Add Comprehensive Test Coverage

Summary

This PR improves the warning message in the Grape::Util::Registry module and adds comprehensive test coverage to ensure the registry functionality works correctly across various scenarios.

Changes Made

1. Enhanced Warning Message

File: lib/grape/util/registry.rb

• Before: warn "#{short_name} is already registered with class #{klass}"
• After: warn "#{short_name} is already registered with class #{registry[short_name]}. It will be overridden globally with the following: #{klass.name}"

The warning message now provides more detailed information by:

• Showing the existing class that was previously registered
• Clarifying that the registration will be overridden globally
• Including the name of the new class being registered

2. Comprehensive Test Suite

File: spec/grape/util/registry_spec.rb (new file)

Added 186 lines of comprehensive test coverage including:

Core Functionality Tests

• Registration of classes with different naming patterns (simple, camel case, namespaced)
• Proper handling of invalid class names (anonymous, nil, empty)
• Indifferent access for registry keys (string vs symbol)

Duplicate Registration Tests

• Warning behavior when registering duplicate short names
• Verification that warnings include correct class information
• Confirmation that existing registrations are properly overwritten
• Multiple duplicate registration scenarios

Edge Cases

• Classes with special characters and multiple modules
• Classes with numbers in names
• Classes with acronyms (API, HTTP, etc.)

Why This Change Matters

1. Better Debugging: The enhanced warning message provides developers with more context when duplicate registrations occur, making it easier to identify and resolve conflicts.

2. Improved User Experience: Users of the Grape framework will now receive clearer feedback about what's happening during registration conflicts.

3. Comprehensive Testing: The new test suite ensures the registry functionality is robust and handles edge cases properly, preventing regressions in future changes.

Testing

The changes include comprehensive test coverage that verifies:

• ✅ All existing functionality continues to work
• ✅ Warning messages are properly formatted and informative
• ✅ Edge cases are handled gracefully
• ✅ Registry behavior is consistent across different class naming patterns

Breaking Changes

None. This is a backward-compatible improvement that only enhances the warning message and adds test coverage.

Related Issues

Fix #2591