error: add more document

Author: zchee

error.go

@@ -17,22 +17,33 @@ type Code int64
 const (
 	// ParseError is the invalid JSON was received by the server. An error occurred on the server while parsing the JSON text.
 	ParseError = Code(-32700)
+
 	// InvalidRequest is the JSON sent is not a valid Request object.
 	InvalidRequest = Code(-32600)
+
 	// MethodNotFound is the method does not exist / is not available.
 	MethodNotFound = Code(-32601)
+
 	// InvalidParams is the invalid method parameter(s).
 	InvalidParams = Code(-32602)
+
 	// InternalError is the internal JSON-RPC error.
 	InternalError = Code(-32603)
 
 	// ServerNotInitialized is the error of server not initialized.
 	ServerNotInitialized = Code(-32002)
+
 	// UnknownError should be used for all non coded errors.
 	UnknownError = Code(-32001)
+
 	// RequestCancelled is the cancellation error.
+	//
+	// Defined by the Language Server Protocol.
 	RequestCancelled = Code(-32800)
+
 	// ContentModified is the state change that invalidates the result of a request in execution.
+	//
+	// Defined by the Language Server Protocol.
 	ContentModified = Code(-32801)
 
 	// ServerOverloaded is returned when a message was refused due to a