The guide overview listed only five of the eight public solver backends. Update the Key Features bullet to enumerate all eight in the same alphabetical order used by the solver API reference, and replace the partial enumeration in the Core Concepts Solver bullet with a link to the solver feature matrix so the list is maintained in one place.

Addresses #2183.

Description

Checklist

• New or existing tests cover these changes
• The documentation is up to date with these changes
• CHANGELOG.md has been updated (if user-facing change)

Test plan

Bug fix

Steps to reproduce:

Minimal reproduction:

import newton

# Code that demonstrates the bug

New feature / API change

import newton

# Code that demonstrates the new capability

Summary by CodeRabbit

• Documentation
  • Updated guide overview to comprehensively list all available solver backends (ImplicitMPM, Kamino, MuJoCo SemiImplicit, Style3D, VBD, XPBD) with references to the solver feature matrix for detailed feature comparison information to assist users in selecting appropriate solvers.