add style guide

doc/style.md

@@ -0,0 +1,16 @@
+# Official Style Guide
+
+These conventions are not enforced by the compiler, but they are shipped in
+this documentation along with the compiler in order to provide a point of
+reference, should anyone wish to point to an authority on agreed upon Zig
+coding style.
+
+ * 4 space indentation
+ * `camelCaseFunctionName`
+ * `TitleCaseTypeName`
+ * `snake_case_variable_name`
+ * Open braces on same line, unless you need to wrap.
+ * If a list of things is longer than 2, put each item on its own line and
+   exercise the abilty to put an extra comma at the end.
+
+See Zig standard library for examples.