Dead links in linear_algebra page

[mcol]

On this page the following are broken (some appear multiple times in the page):

• algebra.module
• algebra.pi_instances
• smul_eq_mul
• linear_algebra.matrix
• linear_algebra.nonsingular_inverse
• antiautomorphism
• bilin_form.to_quadratic_form f
• linear_algebra.quadratic_form

[jcommelin]

Thanks for reporting these! And my apologies for the long delay in actually fixing them.