message: Fix typos in contribution guide
diff: #### Bug Reports
  Please provide a (**simple**) way to reproduce the problem.
  -A bug that can not be reproduced is less likely be solved.
  +A bug that can not be reproduced is less likely to be solved.
  #### Feature Requests
  @@ -26,7 +26,7 @@ See some [existing examples][examples] to get started.
  Details:
  -- An Example **must** include some tests with an **\_spec.js** suffix.
  +- An Example **must** include some tests with a **\_spec.js** suffix.
  #### Contributing To Chevrotain's Runtime Source code.
  @@ -34,7 +34,7 @@ This can be more complex as more in-depth knowledge of chevrotain internals may
  Details:
  -- ~100% code coverage is **required**.
  +- ~100% test coverage is **required**.
  - It is possible to disable coverage for specific code, but there must be a very good reason to do so.
  - Try to maintain the same code style used in the rest of Chevrotain's source code.
  - The linting will take care of most of this automatically.
  @@ -50,7 +50,7 @@ Examine the [package.json][package] scripts for all the available tasks:
  #### Some basic dev flows to get started
  -Chevrotain is written using Typescript, so compilation to javascript is needed.
  +Chevrotain is written using Typescript, so compilation to JavaScript is needed.
  - `yarn run compile`
  