refactor: name configurable viewport scroll steps accurately

config.backup.rb

@@ -5,18 +5,29 @@ Vamp.configure do |config|
     "python" => true,
   )
 
+  # fallback tab spaces
+  config.tab_spaces = 4
+
+  # language specific tab spaces
+  config.language_tab_spaces.merge!(
+    "rust" => 4,
+    "ruby" => 2,
+    "makefile" => nil,
+  )
+
   # 0 (default): scroll only at viewport edges
   # nil: center; oversized integer margins also center
   config.scroll_distance = 7
+  config.scroll_step_lines = 3
 
   config.highlight_trailing_whitespace = true
 
-  config.whitespace_scope = "leading" # or "all" (default)
-  config.whitespace_characters = {
-    " " => "·",
-    "\t" => "→",
-    "\n" => "↵",
-  }
+  #config.whitespace_scope = "leading" # or "all" (default)
+  #config.whitespace_characters = {
+  #  " " => "·",
+  #  "\t" => "→",
+  #  "\n" => "↵",
+  #}
 
   # "bar" (default), "symbols", "line_numbers", "none"
   config.git_gutter = "bar"