Implement proper handling for "tight" lists

In the case of a "tight" list--meaning a markdown list with no
padding newline between entries--the inner paragraph generated by
the AST parser is now automatically stripped out as expected.

__tests__/index.js

@@ -315,8 +315,7 @@ describe('markdown-to-jsx', () => {
     });
 
     describe('lists', () => {
-        /* disabled pending a fix from mdast: https://github.com/wooorm/mdast/issues/104 */
-        xit('should handle a tight list', () => {
+        it('should handle a tight list', () => {
             const element = render(converter([
                 '- xyz',
                 '- abc',

index.js

@@ -166,6 +166,19 @@ export default function markdownToJSX(markdown, options = {}, overrides = {}) {
             );
         } /* Refers to fenced blocks, need to create a pre:code nested structure */
 
+        if (ast.type === 'list' && ast.loose === false) {
+            ast.children = ast.children.map(item => {
+                if (item.children.length === 1 && item.children[0].type === 'paragraph') {
+                    return {
+                        ...item,
+                        children: item.children[0].children,
+                    };
+                }
+
+                return item;
+            });
+        } /* tight list, remove the paragraph wrapper just inside the listItem */
+
         if (ast.type === 'listItem') {
             if (ast.checked === true || ast.checked === false) {
                 return (