Add cascade and param info to Front Matter and Shortcodes topics

[clayton-cornell]

This PR adds cascade and param info to Front Matter and shortcodes topics in the Writer's Toolkit

[github-actions]

Overall readability score: 60.85 (🟢 +0.02)

File	Readability
index.md	71.49 (🟢 +0.11)
index.md	65.31 (🟢 +0.64)

View detailed metrics

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

File	Readability	FRE	GF	ARI	CLI	DCRS
index.md	71.49	56.86	8.63	9.5	10.37	6.65
	🟢 +0.11	🟢 +0	🔴 -0.03	🟢 +0.1	🟢 +0.06	🔴 -0.02
index.md	65.31	47.38	8.45	11.8	12.29	6.3
	🟢 +0.64	🟢 +0.3	🟢 +0.17	🟢 +0.1	🟢 +0.06	🟢 +0.02

Averages:

	Readability	FRE	GF	ARI	CLI	DCRS
Average	60.85	47.79	9.56	11.6	12.05	7.31
	🟢 +0.02	🟢 +0.01	🟢 +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

[jdbaldry]

Nice! I like this a lot. The cascade documentation is a useful subset of the Hugo docs. There are alternative forms of cascading front matter that can selectively target a page but I think keeping to this single form is valuable because it keeps things simple.

[jdbaldry]

I don't think we should have exclamations in examples since they are discouraged by the style guide.

[clayton-cornell]

I copied this direct from the published docs :-) I'll remove it here.

[clayton-cornell]

alternative forms of cascading

I saw that when I was reading up on cascade. I see it's also used for labels. I only documented the variable... thinking we could expand on this section as we need.