fix(docs-infra): more clearly separate different sections on the "Press kit" page (#40945)
fix(docs-infra): more clearly separate different sections on the "Press kit" page (#40945)

This commit adds a horizontal line and some extra spacing between
different sections of the "Press kit" page to make it easier to identify
where one section ends and the next begins.

Before: ![presskit sections before][1]
After: ![presskit sections after][2]

[1]: https://user-images.githubusercontent.com/8604205/108739638-8208c600-753d-11eb-99bb-ea119640de39.png
[2]: https://user-images.githubusercontent.com/8604205/108745297-95b72b00-7543-11eb-9a35-56325477534b.png

PR Close #40945

shairez/angular,mgechev/angular,manekinekko/angular,shairez/angular,manekinekko/angular,alxhub/angular,ocombe/angular,angular/angular,ocombe/angular,JiaLiPassion/angular,alxhub/angular,alxhub/angular,angular-indonesia/angular,gnomeontherun/angular,alxhub/angular,angular/angular,gnomeontherun/angular,angular/angular,gkalpak/angular,gnomeontherun/angular,gnomeontherun/angular,JiaLiPassion/angular,manekinekko/angular,brandonroberts/angular,brandonroberts/angular,mgechev/angular,ocombe/angular,ocombe/angular,gkalpak/angular,angular-indonesia/angular,manekinekko/angular,angular-indonesia/angular,angular-indonesia/angular,ocombe/angular,mgechev/angular,mgechev/angular,angular/angular,brandonroberts/angular,brandonroberts/angular,mgechev/angular,manekinekko/angular,brandonroberts/angular,alxhub/angular,JiaLiPassion/angular,shairez/angular,JiaLiPassion/angular,manekinekko/angular,gkalpak/angular,ocombe/angular,gkalpak/angular,brandonroberts/angular,shairez/angular,shairez/angular