fix(viewport): normalize method names (#763)

* Reapply "fix(viewport): normalize method names"

This reverts commit f2434c374b.

* test: fixes

* fix: lint

* fix: disable horizontal scroll on v1

it might be a breaking change.

let's enable it by default on v2, and remove the deprecated methods as
well.

cc/ @meowgorithm

* fix: simplify

textarea/textarea.go

@@ -857,9 +857,9 @@ func (m *Model) repositionView() {
 	maximum := minimum + m.viewport.Height - 1
 
 	if row := m.cursorLineNumber(); row < minimum {
-		m.viewport.LineUp(minimum - row)
+		m.viewport.ScrollUp(minimum - row)
 	} else if row > maximum {
-		m.viewport.LineDown(row - maximum)
+		m.viewport.ScrollDown(row - maximum)
 	}
 }
 

textarea/textarea_test.go

@@ -43,7 +43,7 @@ func TestVerticalScrolling(t *testing.T) {
 		"the text area.",
 	}
 	for _, line := range lines {
-		textarea.viewport.LineDown(1)
+		textarea.viewport.ScrollDown(1)
 		view = textarea.View()
 		if !strings.Contains(view, line) {
 			t.Log(view)