Handlebars identified as Harbour

## Preliminary Steps

Please confirm you have...
- [x] reviewed [How Linguist Works](https://github.com/github/linguist#how-linguist-works),
- [x] reviewed the [Troubleshooting](https://github.com/github/linguist#troubleshooting) docs,
- [x] considered implementing an [override](https://github.com/github/linguist#overrides),
- [x] verified an issue has not already been logged for your issue ([linguist issues](https://github.com/issues?utf8=%E2%9C%93&q=is%3Aissue+repo%3Agithub/linguist)).

## Problem Description
`.hb` is currently associated to `Harbour`, but it is also used for `Handlebars`. Linguist currently classifies Handlebars files with `.hb` extension as `Harbour`.

### URL of the affected repository:
* [extension:hb div](https://github.com/search?q=extension%3Ahb+div&type=Code)
* [extension:hb html](https://github.com/search?p=30&q=extension%3Ahb+html&type=Code)

### Last modified on:
2019-11-27

### Expected language:
Handlebars

### Detected language:
Harbour