chore(tooling): Update editor-config key for stylua as accepted upstream

Our setting addition is still not in a tagged release, but the PR was
accepted into the default branch of stylua. This means you no longer
need to run my fork of Stylua to get this project's style, you just nead
any build from the main development branch. However the config key was
renamed as part of the acceptance, so this is the relevant adjustment.

.editorconfig

@@ -24,7 +24,7 @@ max_line_length = 120
 
 # StyLua keys
 collapse_simple_statement = never
-space_after_functions = definitions
+space_after_function_names = definitions
 
 # EmmyLuaCodeStyle keys
 continuation_indent = 6