Documentation Improvements

Cleaned up the LaTeX in examples and documentation of FORM. Also reorganized some of the logic for FORM convergence criteria to be more legible, while maintaining logical flow.

Description

Removed duplicate import statements, fixed typos in English and LaTeX in FORM documentation, added failure_probability attribute to documentation, alphabetized attributes, replaced generic variable names with correctly capitalized specific variable names.

Related Issue

Issue #194 noted a duplicate import statement in an example.

Motivation and Context

These changes improve the legibility of the logic flow in FORM and make its documentation more specific and useful.

How Has This Been Tested?

All existing FORM tests for convergence, accuracy, and input/output types are still in place and passed.

Screenshots (if appropriate):

No applicable screenshots.

Types of changes

What types of changes does your code introduce? Put an x in all the boxes that apply:

[x] Bug fix (non-breaking change which fixes an issue)
[ ] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

Go over all the following points, and put an x in all the boxes that apply. If you're unsure about any of these, don't hesitate to ask. We're here to help!