feat: Add Nim language server support via nimlangserver

[zerone0x]

Summary

Adds support for the Nim programming language using nimlangserver, resolving #645.

Changes

• New language server: src/solidlsp/language_servers/nim_language_server.py
  • NimLanguageServer class using nimlangserver executable
  • Supports stdio communication
  • Checks for nimlangserver availability with a helpful error message on failure
• Language registration: Added Language.NIM = "nim" to the enum in ls_config.py with .nim and .nims file matchers and factory integration
• Test repository: test/resources/repos/nim/test_repo/
  • src/calculator.nim: Arithmetic procedures (add, subtract, multiply, divide, factorial, power)
  • src/utils.nim: String utilities (trim, startsWith, endsWith, split, join)
  • main.nim: Entry point referencing both modules
  • test_repo.nimble: Project file
• Tests: test/solidlsp/nim/test_nim_basic.py
  • Symbol discovery in calculator.nim, utils.nim, and main.nim
  • Cross-file reference tests for calculator.add and utils.trim
  • Tests are skipped when nimlangserver is not installed
• Documentation: Updated README.md, docs/01-about/020_programming-languages.md, and CHANGELOG.md

Installation

Nim can be installed from https://nim-lang.org/install.html

Testing

Tests are skipped automatically when nimlangserver is not installed:

[MischaPanch]

Hi @zerone0x . We have a long-standing open PR for nim support that has gone through multiple review rounds #658 . It's actually fairly close to being merged, though it had to resort to a lot of hacks. Could you maybe have a look at it, check the differences to yours, maybe review/comment there?

[zerone0x]

Hi @zerone0x . We have a long-standing open PR for nim support that has gone through multiple review rounds #658 . It's actually fairly close to being merged, though it had to resort to a lot of hacks. Could you maybe have a look at it, check the differences to yours, maybe review/comment there?

Sure, thanks for reminding.