Fix Lobatto exactness

[inducer]

Closes gh-162

[Copilot]

Pull request overview

Fixes the reported Lobatto quadrature exactness metadata (gh-162) by correcting the documented/published degree of exactness to align with the standard Gauss–Lobatto formula for N+1 nodes.

Changes:

• Update JacobiGaussLobattoQuadrature docstring exactness from 2N-3 to 2N-1.
• Update the exact_to value passed to the Quadrature base class from 2N-3 to 2N-1.

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[Copilot]

Pull request overview

This PR fixes the reported polynomial exactness for the Jacobi/Legendre Gauss–Lobatto quadrature rules (gh-162) by correcting the documented and exported exact_to degree to match the standard Lobatto formula for N+1 nodes.

Changes:

• Update Gauss–Lobatto exactness documentation from :math:2N-3 to :math:2N-1 for N+1 nodes.
• Update JacobiGaussLobattoQuadrature to report exact_to = 2*N - 1 via the base Quadrature initializer.

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