Add support for GraphQL (resolves highlightjs#1471)

AUTHORS.en.txt

@@ -252,3 +252,4 @@ Contributors:
 - Nicolas LLOBERA <nllobera@gmail.com>
 - Morten Piibeleht <morten.piibeleht@gmail.com>
 - Martin Clausen <martin.clausene@gmail.com>
+- David Peek <mail@dpeek.com>

AUTHORS.ru.txt

@@ -252,3 +252,4 @@ URL:   https://highlightjs.org/
 - Николя Ллобера <nllobera@gmail.com>
 - Мортен Пибелехт <morten.piibeleht@gmail.com>
 - Мартин Клаузен <martin.clausene@gmail.com>
+- Давид Пээк <mail@dpeek.com>

CHANGES.md

@@ -1,3 +1,9 @@
+## Version 9.13.0
+
+New language:
+
+- *GraphQL* graph query language by [David Peek][].
+
 ## Version 9.12.0
 
 New language:

src/languages/graphql.js

@@ -0,0 +1,41 @@
+/*
+Language: GraphQL
+Author: David Peek <mail@dpeek.com>
+Description: GraphQL schema, query, mutation and subscription
+*/
+
+function(hljs) {
+  return {
+    aliases: ['gql'],
+    keywords: {
+      keyword: 'query mutation subscription type interface union scalar fragment enum on ...',
+      literal: 'true false null'
+    },
+    contains: [
+      hljs.HASH_COMMENT_MODE,
+      hljs.QUOTE_STRING_MODE,
+      hljs.NUMBER_MODE,
+      { className: 'type',
+        begin: '[^\\w][A-Z][a-z]', end: '\\W',
+        excludeEnd: true
+      },
+      { className: 'literal',
+        begin: '[^\\w][A-Z][A-Z]', end: '\\W',
+        excludeEnd: true
+      },
+      { className: 'variable',
+        begin: '\\$', end: '\\W',
+        excludeEnd: true
+      },
+      {
+        className: 'keyword',
+        begin: '[.]{2}', end: '\\.',
+      },
+      {
+        className: 'meta',
+        begin: '@', end: '\\W',
+        excludeEnd: true
+      }
+    ]
+  }
+}

test/detect/graphql/default.txt

@@ -0,0 +1,63 @@
+# Comment
+
+type ComplexType {
+  name: String!
+}
+
+enum EnumType {
+  MOBILE
+  DESKTOP
+}
+
+union UnionType = ComplexType | EnumType
+
+query queryName($foo: ComplexType, $site: Site = MOBILE) {
+  whoever123is: node(id: [123, 456]) {
+    id ,
+    ... on User @defer {
+      field2 {
+        id ,
+        alias: field1(first:10, after:$foo,) @include(if: $foo) {
+          id,
+          ...frag
+        }
+      }
+    }
+    ... @skip(unless: $foo) {
+      id
+    }
+    ... {
+      id
+    }
+  }
+}
+
+mutation likeStory {
+  like(story: 123) @defer {
+    story {
+      id
+    }
+  }
+}
+
+subscription StoryLikeSubscription($input: StoryLikeSubscribeInput) {
+  storyLikeSubscribe(input: $input) {
+    story {
+      likers {
+        count
+      }
+      likeSentence {
+        text
+      }
+    }
+  }
+}
+
+fragment frag on Friend {
+  foo(size: $size, bar: $b, obj: {key: "value"})
+}
+
+{
+  unnamed(truthy: true, falsey: false, nullish: null),
+  query
+}