[docs] Fix `IterationSummary` section. Add missing `IterationCallback` Change-Id: I1d10201cd927003fd3d46728d13231d3fbc27f96
Ceres Solver is an open source C++ library for modeling and solving large, complicated optimization problems. It is a feature rich, mature and performant library which has been used in production at Google since 2010. Ceres Solver can solve two kinds of problems.
Please see ceres-solver.org for more information.