Add comprehensive rename functionality tests for nimlsp

[bung87]

Add comprehensive rename functionality tests for nimlsp

Summary

This PR adds a comprehensive test suite for the textDocument/rename LSP functionality, including cross-file rename testing and documentation of current limitations.

Changes Made

New Test Files

• tests/trename.nim - Main test file for textDocument/rename functionality
• tests/rename_test_project/ - Test project with multiple files for cross-file testing
  • rename_test.nim - Source file with exported variables, functions, and constants
  • other_file.nim - Importing file that references symbols from the main file
  • rename_test.nimble - Nimble project configuration
• tests/run_rename_test.nim - Test runner script

Test Coverage

The test suite covers:

• ✅ Variable renaming - Tests renaming exported variables
• ✅ Function renaming - Tests renaming exported functions
• ✅ Constant renaming - Tests renaming exported constants
• ✅ Cross-file renaming - Tests renaming from both definition and usage files
• ✅ Response validation - Verifies proper LSP response structure and text edits
• ✅ Version warning handling - Gracefully handles nimlsp version mismatch warnings

Key Findings

During testing, we discovered an important limitation in the current nimlsp implementation:

Cross-file rename behavior:

• ✅ Rename from usage/import file: Updates both definition and usage files
• ❌ Rename from definition file: Only updates the definition file

This reveals a limitation in nimlsp/nimsuggest symbol resolution where cross-file references are only detected when the rename request originates from the file that imports/uses the symbol.

Test Output

The test includes explanatory output that documents this behavior:

[NOTE] Cross-file rename: Only renaming from the usage/import file updates both files.
Renaming from the definition file only updates the definition file.
This is a current limitation of nimlsp/nimsuggest symbol resolution.

[PMunch]

Very nice to have some tests! I have noticed the "Rename from definition file" bug before. But haven't gotten around to fix it. It's probably just a matter of figuring out which nimsuggest commands would give the right list of symbols.

[bung87]

yeah, I rarely use rename function in nim project, but likely it doesn't work well every time during these years, so I let AI help me write this test to see what's in the deep.