feat: add word_del_strikethrough config option

doc/inline-diff.txt

@@ -27,6 +27,7 @@ Call `setup()` once in your config. All arguments are optional: >lua
 
     require("inline-diff").setup({
       debounce_ms = 150,  -- ms to wait after last keystroke
+      word_del_strikethrough = true,  -- strikethrough deleted words in changed lines
     })
 <
 
@@ -38,6 +39,12 @@ Options ~
       Milliseconds to wait after the last keystroke before recomputing the
       diff. Raise this value if you notice CPU usage during fast typing.
 
+  word_del_strikethrough                  *inline-diff-config-word_del_strikethrough*
+      Type: `boolean`, Default: `true`
+      When `true`, words deleted within a changed line are shown with a
+      strikethrough. Set to `false` to render them with the same solid
+      background as fully removed lines.
+
 ==============================================================================
 COMMANDS                                                  *inline-diff-commands*
 
@@ -104,7 +111,8 @@ Colors are derived automatically from your colorscheme's `DiffAdd` and
 
   InlineDiffWordDel       *hl-InlineDiffWordDel*
       Background of individual deleted words in virtual lines
-      (brighter than InlineDiffDelete, strikethrough).
+      (brighter than InlineDiffDelete; strikethrough unless
+      `word_del_strikethrough` is `false`).
 
 Override any group after `setup()` or inside a `ColorScheme` autocmd: >lua
 

lua/inline-diff/highlight.lua

@@ -1,5 +1,7 @@
 local M = {}
 
+M.word_del_strikethrough = true
+
 function M._rgb_to_hsl(rgb)
   local r = bit.rshift(bit.band(rgb, 0xFF0000), 16) / 255
   local g = bit.rshift(bit.band(rgb, 0x00FF00), 8) / 255
@@ -90,7 +92,11 @@ function M.define()
   vim.api.nvim_set_hl(0, "InlineDiffAdd", { bg = add_bg, fg = M._contrast_fg(add_bg) })
   vim.api.nvim_set_hl(0, "InlineDiffDelete", { bg = del_bg, fg = M._contrast_fg(del_bg) })
   vim.api.nvim_set_hl(0, "InlineDiffWordAdd", { bg = word_add_bg, fg = M._contrast_fg(word_add_bg) })
-  vim.api.nvim_set_hl(0, "InlineDiffWordDel", { bg = word_del_bg, fg = M._contrast_fg(word_del_bg), strikethrough = true })
+  local word_del_hl = { bg = word_del_bg, fg = M._contrast_fg(word_del_bg) }
+  if M.word_del_strikethrough ~= false then
+    word_del_hl.strikethrough = true
+  end
+  vim.api.nvim_set_hl(0, "InlineDiffWordDel", word_del_hl)
 end
 
 function M.setup_autocmd()

lua/inline-diff/init.lua

@@ -40,10 +40,12 @@ end
 
 M.config = {
   debounce_ms = 150,
+  word_del_strikethrough = true,
 }
 
 function M.setup(opts)
   M.config = vim.tbl_deep_extend("force", M.config, opts or {})
+  highlight.word_del_strikethrough = M.config.word_del_strikethrough
   highlight.define()
   highlight.setup_autocmd()
 end
@@ -225,6 +227,7 @@ function M.enable(bufnr, ref)
   s.ref = ref
 
   -- Ensure highlights are defined
+  highlight.word_del_strikethrough = M.config.word_del_strikethrough
   highlight.define()
 
   -- Initial refresh

tests/highlight_spec.lua

@@ -94,3 +94,21 @@ describe("_boost_color", function()
     assert.is_true(math.abs((l_out - l_in) - 0.22) < 0.02, "lightness delta should be ~0.22")
   end)
 end)
+
+describe("define / word_del_strikethrough", function()
+  local function word_del_attrs()
+    return vim.api.nvim_get_hl(0, { name = "InlineDiffWordDel", link = false })
+  end
+
+  it("defaults to strikethrough", function()
+    highlight.word_del_strikethrough = nil
+    highlight.define()
+    assert.is_true(word_del_attrs().strikethrough, "strikethrough should default to true")
+  end)
+
+  it("honors word_del_strikethrough = false", function()
+    highlight.word_del_strikethrough = false
+    highlight.define()
+    assert.is_nil(word_del_attrs().strikethrough, "strikethrough should be absent when disabled")
+  end)
+end)