docs: generate docs

Author: sandersn

README.md

@@ -1016,7 +1016,7 @@ function quux (foo) {
 }
 // Settings: {"jsdoc":{"additionalTagNames":{"customTags":["baz","bar"]}}}
 
-/**
+/** 
  * @abstract
  * @access
  * @alias
@@ -1104,9 +1104,9 @@ RegExp
 <a name="eslint-plugin-jsdoc-rules-check-types-why-not-capital-case-everything"></a>
 #### Why not capital case everything?
 
-Why are `boolean`, `number` and `string` exempt from starting with a capital letter? Let's take `string` as an example. In Javascript, everything is an object. The string Object has prototypes for string functions such as `.toUpperCase()`.
+Why are `boolean`, `number` and `string` exempt from starting with a capital letter? Let's take `string` as an example. In Javascript, everything is an object. The string Object has prototypes for string functions such as `.toUpperCase()`. 
 
-Fortunately we don't have to write `new String()` everywhere in our code. Javascript will automatically wrap string primitives into string Objects when we're applying a string function to a string primitive. This way the memory footprint is a tiny little bit smaller, and the [GC](https://en.wikipedia.org/wiki/Garbage_collection_(computer_science)) has less work to do.
+Fortunately we don't have to write `new String()` everywhere in our code. Javascript will automatically wrap string primitives into string Objects when we're applying a string function to a string primitive. This way the memory footprint is a tiny little bit smaller, and the [GC](https://en.wikipedia.org/wiki/Garbage_collection_(computer_science)) has less work to do. 
 
 So in a sense, there two types of strings in Javascript; `{string}` literals, also called primitives and `{String}` Objects. We use the primitives because it's easier to write and uses less memory. `{String}` and `{string}` are technically both valid, but they are not the same.
 
@@ -2464,7 +2464,6 @@ The following patterns are considered problems:
  */
 function quux (foo) {
 
-  return foo;
 }
 // Message: Present JSDoc @returns declaration but not available return expression in function.
 
@@ -2473,7 +2472,6 @@ function quux (foo) {
  */
 function quux (foo) {
 
-  return foo;
 }
 // Settings: {"jsdoc":{"tagNamePreference":{"returns":"return"}}}
 // Message: Present JSDoc @return declaration but not available return expression in function.
@@ -2483,6 +2481,16 @@ function quux (foo) {
  */
 const quux = () => {}
 // Message: Present JSDoc @returns declaration but not available return expression in function.
+
+/**
+ * @returns {undefined} Foo.
+ * @returns {String} Foo.
+ */
+function quux () {
+
+  return foo;
+}
+// Message: Found more than one @returns declaration.
 ````
 
 The following patterns are not considered problems:
@@ -2523,15 +2531,23 @@ function quux () {
  */
 const quux = () => foo;
 
-/**
+/** 
  * @returns {Promise<void>}
  */
 async function quux() {}
 
-/**
+/** 
  * @returns {Promise<void>}
  */
 async () => {}
+
+/** 
+ * @returns Foo.
+ * @abstract
+ */
+function quux () {
+  throw new Error('must be implemented by subclass!');
+}
 ````