When commenting, use the language after the line start, not before

FIX: Fix an issue where creating a comment for a line that starts an
inner language would use the comment style from the outer language.

Closes codemirror/dev#1544

Author: marijnh

src/comment.ts

@@ -61,7 +61,7 @@ export const toggleBlockCommentByLine =
   command((o, s) => changeBlockComment(o, s, selectedLineRanges(s)), CommentOption.Toggle)
 
 function getConfig(state: EditorState, pos: number) {
-  let data = state.languageDataAt<CommentTokens>("commentTokens", pos)
+  let data = state.languageDataAt<CommentTokens>("commentTokens", pos, 1)
   return data.length ? data[0] : {}
 }