Enabling Prettier formatting on JSON files

[Mark Banner]

After the merges next week (~9 May), I plan to land patches enabling Prettier for the formatting of JSON files in the mozilla-central tree.

JSON files in crashtests and reftest directories are ignored by default, as are those listed in Generated.txt and ThirdPartyPaths.txt. There are also additional files we will be ignoring which are shown in the patch for enabling the configuration.

If you know of any other JSON files that should be ignored, please comment on the bug including the reason(s) for ignoring them.

At the moment, we are not enabling any ESLint rules on these files, that is something that we will look into later. For now, this is a first step for upgrading Prettier and extending it to more files.

Mark.

[Mark Banner]

These patches have now landed on autoland, so should be included in one of the next few merges if no issues are found.

Mark.