Update CONTRIBUTING.md

Fixed code highlighting, added more coding style rules, added link to how to do draft prs.

Author: tilkinsc

CONTRIBUTING.md

@@ -1,7 +1,7 @@
 ## How to Contribute
 
 1. Follow the code style
-```C#
+```cs
 if ()
 {
 
@@ -16,7 +16,7 @@ catch (...)
 
 }
 
-if ()
+if (...)
 	return;
 
 for (int i = 0; i<=1; i++)
@@ -32,15 +32,26 @@ while (...)
 private int _name;
 public int Name;
 public int Name { get; private set; }
+Do not use var.
 
 public void Example(int argName)
 {
 
 }
+
+using (...)
+{
+
+}
+
+~bit
+~(bit ^ 0xFF)
+((bit & 0xFF) | 0xFF) >> 0xFF
 ```
 
 2. Push changes to a new local branch to the 'dev' branch. ('contributor-feature' -> 'dev')
-3. You are encouraged to start a PR early so we can spy on what you are working on!
+3. You are encouraged to start a PR early so we can spy on what you are working on! [How to do that](https://github.blog/2019-02-14-introducing-draft-pull-requests/)
 4. Versions should not be bumped at all
 5. gitignore is free game add anything that fits
 6. Do not use #region
+7. Tabs only. Spaces will not be accepted.