Make toggleBlockCommentByLine not affect lines with no text selected

FIX: Change `toggleBlockCommentByLine` to not affect lines with the selection
end right at their start.

See https://discuss.codemirror.net/t/togglecomment-after-triple-click-line-selection/8720

Author: marijnh

src/comment.ts

@@ -113,6 +113,8 @@ function selectedLineRanges(state: EditorState) {
   for (let r of state.selection.ranges) {
     let fromLine = state.doc.lineAt(r.from)
     let toLine = r.to <= fromLine.to ? fromLine : state.doc.lineAt(r.to)
+    if (toLine.from > fromLine.from && toLine.from == r.to)
+      toLine = r.to == fromLine.to + 1 ? fromLine : state.doc.lineAt(r.to - 1)
     let last = ranges.length - 1
     if (last >= 0 && ranges[last].to > fromLine.from) ranges[last].to = toLine.to
     else ranges.push({from: fromLine.from + /^\s*/.exec(fromLine.text)![0].length, to: toLine.to})

test/test-comment.ts

@@ -185,6 +185,14 @@ describe("comment", () => {
         checkLine(`on|e\nt|w|o\nth|ree`,
                   `${o} on|e\nt|w|o\nth|ree ${c}`)
       })
+
+      it("doesn't include lines that the selection stops at the start of", () => {
+        checkLine(`|one\n|two`, `${o} |one ${c}\n|two`)
+      })
+
+      it("does include lines with cursor selection at the start", () => {
+        checkLine(`|one\ntwo`, `|${o} one ${c}\ntwo`)
+      })
     })
   }