Fixed skip matrix in examples

[shakedregev]

Description

Currently our examples do a complete factorization at matrix number 1. This is because matrix 0's pivoting sequence does not work for the rest of the sequence. This creates the misconception that it is necessary to fully factorize twice before refactorization for users.

Proposed changes

I removed the pathological 0 matrix from the examples. Matrices should now be 1 indexed (as opposed to 0 indexed).

Checklist

• All tests pass (make test and make test_install per testing instructions). Code tested on
  • CPU backend
  • CUDA backend
  • HIP backend
• I have manually run the non-experimental examples and verified that residuals are close to machine precision. (In your build directory run:
  ./examples/<your_example>.exe -h to get instructions how to run examples). Code tested on:
  • CPU backend
  • CUDA backend
  • HIP backend
• Code compiles cleanly with flags -Wall -Wpedantic -Wconversion -Wextra.
• The new code follows Re::Solve style guidelines.
• There are unit tests for the new code.
• The new code is documented.
• The feature branch is rebased with respect to the target branch.
• I have updated CHANGELOG.md to reflect the changes in this PR. If this is a minor PR that is part of a larger fix already included in the file, state so.