v0.43.6

AbstractAlgebra v0.43.6

Diff since v0.43.5

Merged pull requests:

• Better unsafe funcs for UnivPoly and a few others (#1838) (@fingolfin)
• Add is_finite methods for various ring types (#1842) (@fingolfin)
• Provide a default isapprox method for ring elements (#1843) (@fingolfin)
• Unsafe funcs for FreeAssAlgebra, Poly, MPoly (#1847) (@lgoettgens)
• Merge MatSpace and Generic.MatSpace (#1849) (@lgoettgens)
• Some MatrixRing fixes (#1852) (@lgoettgens)
• Require non-zero coefficient ring in universal polynomial ring (#1858) (@lgoettgens)
• Require non-zero coefficient ring in free associative algebra (#1859) (@lgoettgens)
• Require non-zero coefficient ring in power series ring (#1860) (@lgoettgens)
• Require non-zero coefficient ring in laurent/puiseux constructions (#1861) (@lgoettgens)
• Version 0.43.6 (#1862) (@fingolfin)

Closed issues:

• Add mutating arithmetics for FreeAssociativeAlgebraElem (#1819)
• Merge Generic.MatSpace and MatSpace (#1840)
• Prevent negative dimension matrix rings (#1851)