Add lang/type completion support

This commit...

1. adds `language` to list of supported tag attributes
   used to detect script language.
2. adds dedicated meta scopes for `lang` and `type` attributes
3. adds completions for those values.

Follows sublimehq/Packages#4061

HTML (CoffeeScript).sublime-syntax

@@ -14,12 +14,12 @@ contexts:
 
   script-common:
     - meta_prepend: true
-    - match: (?i:lang){{attribute_name_break}}
-      scope: meta.attribute-with-value.html entity.other.attribute-name.html
+    - match: (?i:lang(?:uage)?){{attribute_name_break}}
+      scope: meta.attribute-with-value.lang.html entity.other.attribute-name.html
       set: script-lang-attribute-assignment
 
   script-lang-attribute-assignment:
-    - meta_content_scope: meta.tag.script.begin.html meta.attribute-with-value.html
+    - meta_content_scope: meta.tag.script.begin.html meta.attribute-with-value.lang.html
     - match: =
       scope: punctuation.separator.key-value.html
       set: script-lang-attribute-value
@@ -28,26 +28,37 @@ contexts:
 
   script-lang-attribute-value:
     - meta_include_prototype: false
-    - meta_scope: meta.tag.script.begin.html meta.attribute-with-value.html
+    - meta_scope: meta.tag.script.begin.html meta.attribute-with-value.lang.html
     - match: (?=(?i:coffee{{unquoted_attribute_break}}|'coffee'|"coffee"))
       set:
         - script-coffee
-        - tag-generic-attribute-meta
+        - tag-lang-attribute-meta
         - tag-generic-attribute-value
     - match: (?=\S)
       set:
         - script-javascript
-        - tag-generic-attribute-meta
+        - tag-lang-attribute-meta
         - tag-generic-attribute-value
 
+  tag-lang-attribute-meta:
+    - meta_include_prototype: false
+    - meta_scope: meta.attribute-with-value.lang.html
+    - include: immediately-pop
+
   script-type-decider:
     - meta_prepend: true
     - match: (?={{coffee_mime_type}}{{unquoted_attribute_break}}|'{{coffee_mime_type}}'|"{{coffee_mime_type}}")
       set:
         - script-coffee
-        - tag-generic-attribute-meta
+        - tag-type-attribute-meta
         - tag-generic-attribute-value
 
+  tag-type-attribute-meta:
+    # required until ST4184
+    - meta_include_prototype: false
+    - meta_scope: meta.attribute-with-value.type.html
+    - include: immediately-pop
+
   script-coffee:
     - meta_include_prototype: false
     - meta_scope: meta.tag.script.begin.html
@@ -86,4 +97,4 @@ contexts:
 variables:
 
   coffee_mime_type: |-
-    (?xi: (?: (?: application |text ) / coffee(?:script)? ) {{mime_type_parameters}}? )
+    (?xi: (?: (?: application | text ) / coffee(?:script)? ) {{mime_type_parameters}}? )

Script Lang Values.sublime-completions

@@ -0,0 +1,10 @@
+{
+	"scope": "text.html meta.tag.script meta.attribute-with-value.lang",
+	"completions": [
+		{
+			"trigger": "coffee",
+			"kind": ["type", "t", "Language Type"],
+			"details": "CoffeeScript"
+		}
+	]
+}

Script Type Values.sublime-completions

@@ -0,0 +1,25 @@
+{
+	"scope": "text.html meta.tag.script meta.attribute-with-value.type",
+	"completions": [
+		{
+			"trigger": "application/coffee",
+			"kind": ["type", "t", "Mime Type"],
+			"details": "CoffeeScript"
+		},
+		{
+			"trigger": "application/coffeescript",
+			"kind": ["type", "t", "Mime Type"],
+			"details": "CoffeeScript"
+		},
+		{
+			"trigger": "text/coffee",
+			"kind": ["type", "t", "Mime Type"],
+			"details": "CoffeeScript"
+		},
+		{
+			"trigger": "text/coffeescript",
+			"kind": ["type", "t", "Mime Type"],
+			"details": "CoffeeScript"
+		}
+	]
+}

tests/syntax_test_scope.html

@@ -28,6 +28,7 @@
 <script lang="coffee">
 # <- meta.tag.script.begin.html punctuation.definition.tag.begin.html
 #^^^^^^^^^^^^^^^^^^^^^ meta.tag.script.begin.html
+#       ^^^^^^^^^^^^^ meta.attribute-with-value.lang.html
 #^^^^^^ entity.name.tag.script.html
 #       ^^^^ entity.other.attribute-name.html
 #           ^ punctuation.separator.key-value.html
@@ -49,3 +50,29 @@
 #^ punctuation.definition.tag.begin.html
 # ^^^^^^ entity.name.tag.script.html
 #       ^ punctuation.definition.tag.end.html
+
+<script language="coffee">
+# <- meta.tag.script.begin.html punctuation.definition.tag.begin.html
+#^^^^^^^^^^^^^^^^^^^^^^^^^ meta.tag.script.begin.html
+#       ^^^^^^^^^^^^^^^^^ meta.attribute-with-value.lang.html
+#^^^^^^ entity.name.tag.script.html
+#       ^^^^^^^^ entity.other.attribute-name.html
+#               ^ punctuation.separator.key-value.html
+#                ^^^^^^^^ meta.string.html string.quoted.double.html
+#                        ^ punctuation.definition.tag.end.html
+    class extends parentClass
+    # <- source.coffee.embedded.html meta.class.coffee keyword.declaration.class.coffee
+    #^^^^^^^^^^^^^^^^^^^^^^^^ source.coffee.embedded.html meta.class
+    #^^^^ keyword.declaration.class.coffee
+    #     ^^^^^^^ storage.modifier.extends.coffee
+    #             ^^^^^^^^^^^ entity.other.inherited-class.coffee
+      constructor: ->
+        return
+    # <- source.coffee.embedded.html
+    #   ^^^^^^ source.coffee.embedded.html keyword.control.flow.coffee
+</script>
+# <- meta.tag.script.end.html punctuation.definition.tag.begin.html
+#^^^^^^^^ meta.tag.script.end.html
+#^ punctuation.definition.tag.begin.html
+# ^^^^^^ entity.name.tag.script.html
+#       ^ punctuation.definition.tag.end.html