Auto merge of #2047 - liquiddandruff:patch-1, r=Valloric

Update tern_runtime directory in README

# PR Prelude

Thank you for working on YCM! :)

**Please complete these steps and check these boxes (by putting an `x` inside
the brackets) _before_ filing your PR:**

- [x] I have read and understood YCM's [CONTRIBUTING][cont] document.
- [x] I have read and understood YCM's [CODE_OF_CONDUCT][code] document.
- [ ] I have included tests for the changes in my PR. If not, I have included a
  rationale for why I haven't.
- [x] **I understand my PR may be closed if it becomes obvious I didn't
  actually perform all of these steps.**

# Why this change is necessary and useful

Was following the guides and saw this referencing a wrong path so I decided to fix it with the proper one.

Should be useful sine this will keep the docs up-to-date!

[cont]: https://github.com/Valloric/YouCompleteMe/blob/master/CONTRIBUTING.md
[code]: https://github.com/Valloric/YouCompleteMe/blob/master/CODE_OF_CONDUCT.md

https://reviewable.io/reviews/valloric/youcompleteme/2047

README.md

@@ -633,7 +633,7 @@ process.
     typescript` after successfully installing [nodejs and npm][npm-install].
 
   - JavaScript support: Install [nodejs and npm][npm-install]. Then navigate to
-    `YouCompleteMe/third_party/ycmd/third_party/tern` and run `npm install
+    `YouCompleteMe/third_party/ycmd/third_party/tern_runtime` and run `npm install
     --production`
 
   - Rust support: Install [rustc and cargo][rust-install]. Navigate to