Typo fixes & ToC fix for Scala guide

Typo fixes in ScalaTemplates.md, ScalaCustomTemplateFormat.md
ToC missing a link between 3.2 Common use Cases to custom format in ScalaHome.md
Don’t escape message content in EventSource #1862
Quick fix for a CI issue in relation to https://github.com/playframework/playframework/pull/1962
Merge pull request #1984 from julienrf/fix/1862

Don’t escape message content in EventSource #1862
Merge pull request #1982 from plepropre/toc_custom_template

Toc custom template : fixing spaces
Merge remote-tracking branch: upstream/master