fix(draft4): typos in descriptions (#269)

couple typos fixed up

* updated attributes for some keywords

content/draft4/validation/additionalItems.markdown

@@ -1,8 +1,8 @@
 ---
 keyword: "additionalItems"
-signature: "Schema"
+signature: "Schema | Boolean"
 value: This keyword must be set to a valid JSON Schema
-summary: "If [`items`](/draft4/validation/items) is set to an array of schemas, validation succeeds if each element of the instance not covered by it validates against this schema."
+summary: "If [`items`](/draft4/validation/items) is set to an array of schemas, validation succeeds if each element of the instance not covered by it validates against this schema. If set to `false`, no additional items are allowed in the array instance."
 kind: [ "applicator" ]
 instance: [ "array" ]
 specification: "https://json-schema.org/draft-04/draft-fge-json-schema-validation-00#rfc.section.5.3.1"

content/draft4/validation/additionalProperties.markdown

@@ -1,8 +1,8 @@
 ---
 keyword: "additionalProperties"
-signature: "Schema"
+signature: "Schema | Boolean"
 value: This keyword must be set to a valid JSON Schema
-summary: "Validation succeeds if the schema validates against each value not matched by other object applicators in this vocabulary."
+summary: "Validation succeeds if the schema validates against each value not matched by other object applicators in this vocabulary. If set to `false`, no additional properties are allowed in the instance."
 kind: [ "applicator" ]
 instance: [ "object" ]
 specification: "https://json-schema.org/draft-04/draft-fge-json-schema-validation-00#rfc.section.5.4.4"

content/draft4/validation/exclusiveMaximum.markdown

@@ -2,7 +2,7 @@
 keyword: "exclusiveMaximum"
 signature: "Boolean"
 value: This keyword must be set to a boolean value
-summary: "When [`maximum`](/draft4/validation/maximum) is present and this keyword is set to true, the numeric instance must be greater than the value in [`maximum`](/draft4/validation/maximum)."
+summary: "When [`maximum`](/draft4/validation/maximum) is present and this keyword is set to true, the numeric instance must be less than the value in [`maximum`](/draft4/validation/maximum)."
 summary: "Validation succeeds if the numeric instance is less than the given number."
 kind: [ "assertion" ]
 instance: [ "number" ]

content/draft4/validation/exclusiveMinimum.markdown

@@ -2,7 +2,7 @@
 keyword: "exclusiveMinimum"
 signature: "Boolean"
 value: This keyword must be set to a boolean value
-summary: "When [`minimum`](/draft4/validation/minimum) is present and this keyword is set to true, the numeric instance must be less than the value in [`minimum`](/draft4/validation/maximum)."
+summary: "When [`minimum`](/draft4/validation/minimum) is present and this keyword is set to true, the numeric instance must be greater than the value in [`minimum`](/draft4/validation/minimum)."
 kind: [ "assertion" ]
 instance: [ "number" ]
 specification: "https://json-schema.org/draft-04/draft-fge-json-schema-validation-00#rfc.section.5.1.3"

content/draft4/validation/items.markdown

@@ -1,6 +1,6 @@
 ---
 keyword: "items"
-signature: "Schema | Array<Schema>"
+signature: "Schema | Array<Schema> | Boolean"
 value: This keyword must be set to a valid JSON Schema or to a *non-empty* array, where each item is a valid JSON Schema
 summary: "If set to a schema, validation succeeds if each element of the instance validates against it, otherwise validation succeeds if each element of the instance validates against the schema at the same position, if any"
 kind: [ "applicator" ]

content/draft4/validation/patternProperties.markdown

@@ -1,6 +1,6 @@
 ---
 keyword: "patternProperties"
-signature: "Object<String, Schema>"
+signature: "Object<String, Schema> | Boolean"
 value: This keyword must be set to an object where each key is a valid [ECMA-262](https://www.ecma-international.org/publications-and-standards/standards/ecma-262/) regular expression and each value is a valid JSON Schema
 summary: "Validation succeeds if, for each instance name that matches any regular expressions that appear as a property name in this keyword's value, the child instance for that name successfully validates against each schema that corresponds to a matching regular expression."
 kind: [ "applicator" ]

content/draft4/validation/properties.markdown

@@ -1,6 +1,6 @@
 ---
 keyword: "properties"
-signature: "Object<String, Schema>"
+signature: "Object<String, Schema> | Boolean"
 value: This keyword must be set to an object where each value is a valid JSON Schema
 summary: "Validation succeeds if, for each name that appears in both the instance and as a name within this keyword's value, the child instance for that name successfully validates against the corresponding schema."
 kind: [ "applicator" ]