Improve documentation (#1344)

doc: fix some typos

- Add missing ".py" for file structure
- Fix slash for Windows path
- Fix word case to match other titles

docs/docs/cli.md

@@ -44,7 +44,7 @@ my-package
 │   └── __init__.py
 └── tests
     ├── __init__.py
-    └── test_my_package
+    └── test_my_package.py
 ```
 
 If you want to name your project differently than the folder, you can pass
@@ -71,7 +71,7 @@ my-package
 │       └── __init__.py
 └── tests
     ├── __init__.py
-    └── test_my_package
+    └── test_my_package.py
 ```
 
 ## init

docs/docs/configuration.md

@@ -28,7 +28,7 @@ Directory where virtualenvs will be created.
 Defaults to one of the following directories:
 
 - macOS:   `~/Library/Caches/pypoetry/virtualenvs`
-- Windows: `C:\Users\<username>\AppData\Local\pypoetry\Cache/virtualenvs`
+- Windows: `C:\Users\<username>\AppData\Local\pypoetry\Cache\virtualenvs`
 - Unix:    `~/.cache/pypoetry/virtualenvs`
 
 ### `repositories.<name>`: string

docs/docs/contributing.md

@@ -70,7 +70,7 @@ Before creating enhancement suggestions, please check [this list](#before-submit
 * **Check that your issue does not already exist in the [issue tracker](https://github.com/sdispater/poetry/issues)**.
 
 
-#### How do I submit an Enhancement suggestion?
+#### How do I submit an enhancement suggestion?
 
 Enhancement suggestions are tracked on the [official issue tracker](https://github.com/sdispater/poetry/issues) where you can create a new one and provide the following information: