Reorder (and restructure) the sections in the README (#678)

* Restructure sections in the README

Previously, the sections were
* Usage
* Supported syntax
* Module Aliases
* New functions, macros, and methods
* Renaming
* New macros
* Other changes
* New types
* Developer tips

This changes them to just
* Usage
* Supported features
* Developer tips

* Sort supported features in README by minimum Compat version

README.md

@@ -42,13 +42,12 @@ the syntax on Julia `master`. However, in a few cases where this is not possible
 a slightly different syntax might be used.
 Please check the list below for the specific syntax you need.
 
-## Supported syntax
+## Supported features
 
-Currently, the `@compat` macro supports the following syntaxes:
-
-## Module Aliases
+* `Base.Order.ReverseOrdering` has a zero arg constructor [#33736]. (since Compat 3.0.0)
 
-## New functions, macros, and methods
+* Function composition now supports multiple functions: `∘(f, g, h) = f ∘ g ∘ h`
+  and splatting `∘(fs...)` for composing an iterable collection of functions ([#33568]).  (since Compat 3.0.0)
 
 * `only(x)` returns the one-and-only element of a collection `x` ([#33129]). (since Compat 2.2.0)
 
@@ -59,24 +58,11 @@ Currently, the `@compat` macro supports the following syntaxes:
 
 * `isnothing` for testing if a variable is equal to `nothing` ([#29674]).  (since Compat 2.1.0)
 
-* `range` supporting `stop` as positional argument ([#28708]). (since Compat 1.3.0)
-
 * `hasproperty` and `hasfield` ([#28850]).  (since Compat 2.0.0)
 
 * `merge` methods with one and `n` `NamedTuple`s ([#29259]). (since Compat 2.0.0)
 
-* `Base.Order.ReverseOrdering` has a zero arg constructor [#33736]. (since Compat 3.0.0)
-
-## Renaming
-
-## New macros
-
-## Other changes
-
-* Function composition now supports multiple functions: `∘(f, g, h) = f ∘ g ∘ h`
-  and splatting `∘(fs...)` for composing an iterable collection of functions ([#33568]).  (since Compat 3.0.0)
-
-## New types
+* `range` supporting `stop` as positional argument ([#28708]). (since Compat 1.3.0)
 
 ## Developer tips