AssumeCM -- an option to assume a ring is Cohen-Macaulay

AssumeCM is an option used in various functions, to assume that a ring is Cohen-Macaulay.

Functions with optional argument named AssumeCM:

• isFInjective(...,AssumeCM=>...) -- see isFInjective -- whether a ring is F-injective
• isFRational(...,AssumeCM=>...) -- see isFRational -- whether a ring is F-rational