Fix headings

Author: cartermp

README.md

@@ -79,15 +79,15 @@ These are the branches in use:
   - May contain new features that depend on new things or fixes in the corresponding forthcoming Visual Studio release.
   - Gets integrated back into master once the corresponding Visual Studio release is made.
 
-### F# language and core library evolution
+## F# language and core library evolution
 
 Although this repository is where actual F# development occurs, evolution of the F# language and core library follows a process spanning two additional repositories. The process is as follows:
 
 1. Use the [F# language suggestions repo](https://github.com/fsharp/fslang-suggestions/) to search for ideas, vote on ones you like, submit new ideas, and discuss details with the F# community.
 2. Ideas that are "approved in principle" are eligible for a new RFC in the [F# language design repo](https://github.com/fsharp/fslang-design). This is where the technical specification and discussion of approved suggestions go.
 3. Implementations and testing of an RFC are submitted to this repository.
 
-### Additional documentation
+## Additional documentation
 
 The following links can help you get an overview of some technical aspects of the F# language and compiler: