Feature: add slope separator (#659)

doc/bufferline.txt

@@ -150,7 +150,7 @@ The available configuration are:
             persist_buffer_sort = true, -- whether or not custom sorted buffers should persist
             -- can also be a table containing 2 custom separators
             -- [focused and unfocused]. eg: { '|', '|' }
-            separator_style = "slant" | "thick" | "thin" | { 'any', 'any' },
+            separator_style = "slant" | "slope" | "thick" | "thin" | { 'any', 'any' },
             enforce_regular_tabs = false | true,
             always_show_bufferline = true | false,
             hover = {
@@ -194,6 +194,7 @@ You can change the appearance of the bufferline separators by setting the
 * `slant` - Use slanted/triangular separators
 * `padded_slant` - Same as `slant` but with extra padding which some terminals require.
   If `slant` does not render correctly for you try padded this instead.
+* `slope` - Use slanted/triangular separators but slopped to the right
 * `thick` - Increase the thickness of the separator characters
 * `thin` - (default) Use thin separator characters
 * finally you can pass in a custom list containing 2 characters which will be

lua/bufferline/constants.lua

@@ -10,6 +10,7 @@ M.sep_names = {
   thin = "thin",
   thick = "thick",
   slant = "slant",
+  slope = "slope",
   padded_slant = "padded_slant",
 }
 
@@ -18,6 +19,7 @@ M.sep_chars = {
   [M.sep_names.thin] = { "▏", "▕" },
   [M.sep_names.thick] = { "▌", "▐" },
   [M.sep_names.slant] = { "", "" },
+  [M.sep_names.slope] = { "", "" },
   [M.sep_names.padded_slant] = { "" .. M.padding, "" .. M.padding },
 }
 

lua/bufferline/ui.lua

@@ -271,7 +271,7 @@ end
 ---@param style string
 ---@return boolean
 local function is_slant(style)
-  return vim.tbl_contains({ sep_names.slant, sep_names.padded_slant }, style)
+  return vim.tbl_contains({ sep_names.slant, sep_names.padded_slant, sep_names.slope}, style)
 end
 
 --- "▍" "░"