fix(*): Add severity, start and end column numbers for diagnostics, change warning to message

src/types/Diagnostic.ts

@@ -1,8 +1,12 @@
+import { Severity } from './Severity'
+
 /**
  * A diagnostic is produced by the execution of a lint rule against a file or line of text.
  */
 export interface Diagnostic {
   lineNumber: number
-  columnNumber: number
-  warning: string
+  startColumnNumber: number
+  endColumnNumber: number
+  message: string
+  severity: Severity
 }