"Referencing Files..." and "Dependencies..." options don't work on editor scripts

**Describe the bug (REQUIRED)**
The "Dependencies..." menu option doesn't list dependencies of editor scripts. Likewise, the "Referencing Files..." menu option doesn't list editor scripts, even when they require the current module.

**To Reproduce (REQUIRED)**
1. Create a new editor script
2. Require a module inside of it
3. Select the "Dependencies..." menu option while viewing the editor script
Also:
4. Open the module that the editor script requires
5. Select the "Referencing Files..." menu option

**Expected behavior (REQUIRED)**
Both menu options should work the same as they do in other script/Lua files.

**Defold version (REQUIRED):**
1.2.172

**Platforms (REQUIRED):**
Tested on:
- macOS 10.14.2
- Manjaro Linux 20.1

Start by tracing the "Dependencies..." and "Referencing Files..." menu entry points for editor scripts and compare them with the behavior for other Lua files. Reproduce the two cases from the issue, then verify that required modules and editor scripts appear in the corresponding results.

Written by the indexing model from the issue text.