Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or other license that is incompatible with OpenCV
• The PR is proposed to proper branch
• There is reference to original bug report and related work
• N/A There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• N/A The feature is well documented and sample code can be built with the project CMake

Fix #17828

• use everywhere camera intrinsic matrix instead of just camera matrix as in A Flexible New Technique for Camera Calibration, Zhengyou Zhang
• add \cameramatrix, \distcoeffs, \distcoeffsfisheye to avoid copy/paste errors, e.g. here (_1) or here (missing subscripts)

Wondering if mymath.sty file is still used? On my computer, it looks like it is MathJax that is used for rendering the formulas.