Fix & normalize Coop frontmatter YAML

Also ensure newline at EOF.

This was achieved by running the new normalize_coop_frontmatter.rb
script which basically reads in the frontmatter, parses it and dumps it
back out.

I had to manually fix some telephone numbers which had been incorrectly
parsed as some kind of number rather than as strings.

_coops/small-axe.md

@@ -55,4 +55,4 @@ We partner with courageous causes to create a better future, from charities and
 
 **Working together**
 
-We’re a group of campaigners with the skills, experience and networks you need to build a social movement in the 21st century.
+We’re a group of campaigners with the skills, experience and networks you need to build a social movement in the 21st century.