Syntax highlighting for Mango queries

[Antonio-Maranhao]

Overview

Adds a custom mode for the Ace Editor that highlights Mango Query operators.
The custom mode also adds warning annotations to the editor's gutter to indicate certain operators can have an adverse impact on query performance.

Before

After

Example of warning annotation:

Testing recommendations

Type a Mango Query in the editor and confirm operators (e.g. $eq) are highlighted on a different color.

GitHub issue number

n/a

Related Pull Requests

n/a

Checklist

• Code is written and works correctly;
• Changes are covered by tests;
• Documentation reflects the changes;
• Update rebar.config.script with the correct tag once a new Fauxton release is made