Failed to activate the ide-python package (webidl-conversions\lib\index.js main entry)

[Enter steps to reproduce:]

1. Install ide-python package
2. Restart Atom
3. Error will occur

**Atom**: 1.53.0 x64
**Electron**: 6.1.12
**OS**: Microsoft Windows 10 Home
**Thrown From**: [ide-python](https://github.com/lgeiger/ide-python) package 1.6.2

### Stack Trace

Failed to activate the ide-python package

```
At Cannot find module 'C:\Users\Floris\.atom\packages\ide-python\node_modules\webidl-conversions\lib\index.js'. Please verify that the package.json has a valid "main" entry

Error: Cannot find module 'C:\Users\Floris\.atom\packages\ide-python\node_modules\webidl-conversions\lib\index.js'. Please verify that the package.json has a valid "main" entry
at tryPackage (internal/modules/cjs/loader.js:232:19)
at Function.Module._findPath (internal/modules/cjs/loader.js:369:18)
at Module._resolveFilename (internal/modules/cjs/loader.js:614:27)
at Module._resolveFilename (~/AppData/Local/atom/app-1.53.0/resources/electron.asar/common/reset-search-paths.js:41:16)
at Function.get_Module._resolveFilename (~/AppData/Local/atom/app-1.53.0/resources/app/static/:11:155481)
at Module.require (/app.asar/static/index.js:61:43)
at require (~/AppData/Local/atom/app-1.53.0/resources/app/static/:11:146814)
at /packages/ide-python/node_modules/domexception/lib/DOMException.js:3:21)
at /packages/ide-python/node_modules/domexception/lib/DOMException.js:370:3)
at Module.get_Module._compile (~/AppData/Local/atom/app-1.53.0/resources/app/static/:11:147498)
at Object.value [as .js] (~/AppData/Local/atom/app-1.53.0/resources/app/static/:11:151046)
at Module.load (internal/modules/cjs/loader.js:645:32)
at Function.Module._load (internal/modules/cjs/loader.js:560:12)
at Module.require (/app.asar/static/index.js:72:46)
at require (~/AppData/Local/atom/app-1.53.0/resources/app/static/:11:146814)
at /packages/ide-python/node_modules/domexception/lib/public-api.js:3:18)
at /packages/ide-python/node_modules/domexception/lib/public-api.js:7:3)
at Module.get_Module._compile (~/AppData/Local/atom/app-1.53.0/resources/app/static/:11:147498)
at Object.value [as .js] (~/AppData/Local/atom/app-1.53.0/resources/app/static/:11:151046)
at Module.load (internal/modules/cjs/loader.js:645:32)
at Function.Module._load (internal/modules/cjs/loader.js:560:12)
at Module.require (/app.asar/static/index.js:72:46)
at require (~/AppData/Local/atom/app-1.53.0/resources/app/static/:11:146814)
at /packages/ide-python/node_modules/@atom-ide-community/nuclide-commons/observable.js:30:44)
at /packages/ide-python/node_modules/@atom-ide-community/nuclide-commons/observable.js:631:3)
at Module.get_Module._compile (~/AppData/Local/atom/app-1.53.0/resources/app/static/:11:147498)
at Object.value [as .js] (~/AppData/Local/atom/app-1.53.0/resources/app/static/:11:151046)
at Module.load (internal/modules/cjs/loader.js:645:32)
at Function.Module._load (internal/modules/cjs/loader.js:560:12)
at Module.require (/app.asar/static/index.js:72:46)
```

### Commands

```
```

### Non-Core Packages

```
autocomplete-python 1.16.0
ide-python 1.6.2
kite undefined
language-arduino 0.4.3
```

从 ide-python package.json 和错误中指出的 node_modules/webidl-conversions/lib/index.js 路径开始。通过 domexception 和 @atom-ide-community/nuclide-commons/observable.js 跟踪依赖链，然后在 Windows 上的 Atom 1.53.0 中复现激活过程。当 ide-python 激活时不再出现缺少模块或主入口无效错误时，即表示完成。

由索引模型根据 Issue 内容生成。