[JavaScript] Move JSON out of the JavaScript package (#1805)

Note from wbond: initial work on splitting JSON happened in 9c44e60, this ties up some loose ends.

As suggested in issue #1771 this commit moves the JSON syntax into a
dedicated package in order to be able to disable either JavaScript or
JSON independently.

This commit does not yet create the suggested compatibility
redirection within the JavaScript package.

The decision about it is left to the core devs right now

1. as it would cause a duplicated syntax file
2. a quick search within packagecontrol.io did not reveal any packages
   depending on the builtin JavaScript/JSON.sublime-syntax
3. the location of the sublime-syntax file should not be too important
   if it is imported via `scope:source.json` or its name
   `JSON.sublime-syntax` only. Conflicts would be caused only if it was
   imported via `Packages/JavaScript/JSON.sublime-syntax` which is easy
   to fix.

JSON/Comments.tmPreferences

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<plist version="1.0">
+<dict>
+	<key>name</key>
+	<string>Comments</string>
+	<key>scope</key>
+	<string>source.json</string>
+	<key>settings</key>
+	<dict>
+		<key>shellVariables</key>
+		<array>
+			<dict>
+				<key>name</key>
+				<string>TM_COMMENT_START</string>
+				<key>value</key>
+				<string>// </string>
+			</dict>
+			<dict>
+				<key>name</key>
+				<string>TM_COMMENT_START_2</string>
+				<key>value</key>
+				<string>/*</string>
+			</dict>
+			<dict>
+				<key>name</key>
+				<string>TM_COMMENT_END_2</string>
+				<key>value</key>
+				<string>*/</string>
+			</dict>
+		</array>
+	</dict>
+</dict>
+</plist>

JSON/Indentation Rules.tmPreferences

@@ -0,0 +1,67 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<plist version="1.0">
+<dict>
+	<key>name</key>
+	<string>JavaScript Indent</string>
+	<key>scope</key>
+	<string>source.json</string>
+	<key>settings</key>
+	<dict>
+		<key>decreaseIndentPattern</key>
+		<string>(?x)
+			# When an object is closed, but not opened
+			(
+				^
+				(
+					# Consume strings
+					"(?:[^"\\]|\\.)*"
+					|
+					# Consume all chars that don't start a string, comment or
+					# open an object on this line
+					[^"/{\n]
+				)*
+				\}.*$
+			)
+			|
+			# When an array is closed by itself on a line (interacts with indentSquareBrackets)
+			(
+				^(.*\*/)?\s*\].*$
+			)
+		</string>
+		<key>increaseIndentPattern</key>
+		<string>(?x)
+			# When an object is opened, but not closed
+			(
+				^.*\{
+				(
+					# Consume strings
+					"(?:[^"\\]|\\.)*"
+					|
+					# Consume all chars that don't start a string, comment or
+					# end the object that was opened on this line
+					[^"/}]
+				)*
+				# Stop matching at the end of the line, or once we hit a comment
+				($|/[/*])
+			)
+			|
+			# When an array is opened, but not closed
+			(
+				^.*\[
+				(
+					# Consume strings
+					"(?:[^"\\]|\\.)*"
+					|
+					# Consume all chars that don't start a string, comment or
+					# end the array that was opened on this line
+					[^"/\]]
+				)*
+				# Stop matching at the end of the line, or once we hit a comment
+				($|/[/*])
+			)
+		</string>
+		<key>indentSquareBrackets</key>
+		<true/>
+	</dict>
+</dict>
+</plist>

JSON/syntax_test_json.json

@@ -1,4 +1,4 @@
-// SYNTAX TEST "Packages/JavaScript/JSON.sublime-syntax"
+// SYNTAX TEST "Packages/JSON/JSON.sublime-syntax"
 
 {
 // <- meta.mapping.json punctuation.section.mapping.begin.json

JavaScript/Comments.tmPreferences

@@ -4,7 +4,7 @@
 	<key>name</key>
 	<string>Comments</string>
 	<key>scope</key>
-	<string>source.js, source.json</string>
+	<string>source.js</string>
 	<key>settings</key>
 	<dict>
 		<key>shellVariables</key>