feat: New Coverage engine - diff coverage toggle ALA-574

[nicklem]

Documents the new diff coverage toggle. It will be available for GitHub only for now.

👀 Live preview

• GitHub
• GitLab (no updates for now)
• Bitbucket (no updates for now)

🚧 To do

• Remove feature for GitLab and Bitbucket.
• Review screenshots. They should already match the prod version.
• Request validation
• Apply feedback
• Wait for feature release

[github-actions]

Overall readability score: 53.13 (🟢 +0.02)

File	Readability
github-integration.md	40.78 (🟢 +3.66)

View detailed metrics

🟢 - Shows an increase in readability
🔴 - Shows a decrease in readability

File	Readability	FRE	GF	ARI	CLI	DCRS
github-integration.md	40.78	24.07	12.07	17	14.91	7.3
	🟢 +3.66	🔴 -0.1	🟢 +0.36	🟢 +0.7	🟢 +0.7	🟢 +0.33

Averages:

	Readability	FRE	GF	ARI	CLI	DCRS
Average	53.13	42.04	10.95	12.7	12.73	7.88
	🟢 +0.02	🟢 +0	🟢 +0	🟢 +0	🟢 +0	🟢 +0

View metric targets

Metric	Range	Ideal score
Flesch Reading Ease	100 (very easy read) to 0 (extremely difficult read)	60
Gunning Fog	6 (very easy read) to 17 (extremely difficult read)	8 or less
Auto. Read. Index	6 (very easy read) to 14 (extremely difficult read)	8 or less
Coleman Liau Index	6 (very easy read) to 17 (extremely difficult read)	8 or less
Dale-Chall Readability	4.9 (very easy read) to 9.9 (extremely difficult read)	6.9 or less

[machadoit]

LGTM!