Rename mapKeys and mapValues to mapKey and mapValue.

mapKey.js

@@ -1,7 +1,7 @@
 import baseAssignValue from './.internal/baseAssignValue.js'
 
 /**
- * The opposite of `mapValues` this method creates an object with the
+ * The opposite of `mapValue` this method creates an object with the
  * same values as `object` and keys generated by running each own enumerable
  * string keyed property of `object` thru `iteratee`. The iteratee is invoked
  * with three arguments: (value, key, object).
@@ -14,12 +14,12 @@ import baseAssignValue from './.internal/baseAssignValue.js'
  * @see mapValues
  * @example
  *
- * mapKeys({ 'a': 1, 'b': 2 }, function(value, key) {
+ * mapKey({ 'a': 1, 'b': 2 }, function(value, key) {
  *   return key + value
  * })
  * // => { 'a1': 1, 'b2': 2 }
  */
-function mapKeys(object, iteratee) {
+function mapKey(object, iteratee) {
   const result = {}
   Object.keys(object).forEach((value, key, object) => {
     baseAssignValue(result, iteratee(value, key, object), value)

mapValue.js

@@ -19,10 +19,10 @@ import baseAssignValue from './.internal/baseAssignValue.js'
  *   'pebbles': { 'user': 'pebbles', 'age': 1 }
  * }
  *
- * mapValues(users, ({ age }) => age)
+ * mapValue(users, ({ age }) => age)
  * // => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)
  */
-function mapValues(object, iteratee) {
+function mapValue(object, iteratee) {
   const result = {}
   Object.keys(object).forEach((value, key, object) => {
     baseAssignValue(result, key, iteratee(value, key, object))