docs: document utility functions

Author: gajus

src/createObjectExpression.js

@@ -7,6 +7,10 @@ import BabelTypes, {
 type InputObjectType = {
   [key: string]: string | InputObjectType
 };
+
+/**
+ * Creates an AST representation of an InputObjectType shape object.
+ */
 const createObjectExpression = (t: BabelTypes, object: InputObjectType): ObjectExpression => {
   const properties = [];
 

src/resolveStringLiteral.js

@@ -8,6 +8,9 @@ import type {
   StyleModuleImportMapType
 } from './types';
 
+/**
+ * Updates the className value of a JSX element using a provided styleName attribute.
+ */
 export default (path: Object, styleModuleImportMap: StyleModuleImportMapType, styleNameAttribute: JSXAttribute): void => {
   const classNameAttribute = path.node.openingElement.attributes
     .find((attribute) => {