feat: configurable code block background inset

## Details

Request: #643

Adds `code.background_inset` option that defines how far from the start
and end of a code block background rendering should start. The default
value of 1 keeps the existing behavior.

By setting the value to 0 you can extend the background highlight logic
to also include the delimitter lines. This interferes with `code.border`
and `code.language` behavior so should only really be done if both of
those are disabled.

Author: MeanderingProgrammer

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 - allow inline code left and right icon highlight to be specified [e9d7409](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/e9d7409c2d604dc12589c00ef922e08e3998e000)
 - improve table start column tracking [2247dcd](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/2247dcd1ff0c223cfa7e317783f89b8d00457ce6)
+- ability to not conceal wikilink destination when there is an alias [d67113f](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/d67113f11384c0dad96fced2f7b91f1fc811e97f)
 
 ### Bug Fixes
 

README.md

@@ -471,6 +471,8 @@ require('render-markdown').setup({
         -- Use a boolean to make behavior apply to all languages.
         -- Borders above & below blocks will continue to be rendered.
         disable_background = { 'diff' },
+        -- Number of lines from start/end to skip rendering background.
+        background_inset = 1,
         -- Width of the code block background.
         -- | block | width of the code block  |
         -- | full  | full width of the window |
@@ -1181,6 +1183,8 @@ require('render-markdown').setup({
         -- Use a boolean to make behavior apply to all languages.
         -- Borders above & below blocks will continue to be rendered.
         disable_background = { 'diff' },
+        -- Number of lines from start/end to skip rendering background.
+        background_inset = 1,
         -- Width of the code block background.
         -- | block | width of the code block  |
         -- | full  | full width of the window |

doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*        For NVIM v0.12.1       Last change: 2026 April 20
+*render-markdown.txt*        For NVIM v0.12.1       Last change: 2026 April 26
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*
@@ -537,6 +537,8 @@ Default Configuration ~
             -- Use a boolean to make behavior apply to all languages.
             -- Borders above & below blocks will continue to be rendered.
             disable_background = { 'diff' },
+            -- Number of lines from start/end to skip rendering background.
+            background_inset = 1,
             -- Width of the code block background.
             -- | block | width of the code block  |
             -- | full  | full width of the window |
@@ -1241,6 +1243,8 @@ Code Block Configuration ~
             -- Use a boolean to make behavior apply to all languages.
             -- Borders above & below blocks will continue to be rendered.
             disable_background = { 'diff' },
+            -- Number of lines from start/end to skip rendering background.
+            background_inset = 1,
             -- Width of the code block background.
             -- | block | width of the code block  |
             -- | full  | full width of the window |

lua/render-markdown/health.lua

@@ -6,7 +6,7 @@ local state = require('render-markdown.state')
 local M = {}
 
 ---@private
-M.version = '8.12.11'
+M.version = '8.12.12'
 
 function M.check()
     M.start('versions')

lua/render-markdown/render/markdown/code.lua

@@ -108,7 +108,8 @@ function Render:run()
 
     local background = self:enabled(self.config.disable_background)
     if background then
-        self:background(start_row + 1, end_row - 1)
+        local inset = self.config.background_inset
+        self:background(start_row + inset, end_row - inset)
     end
     self:padding(background)
 end

lua/render-markdown/settings.lua

@@ -390,6 +390,7 @@ M.code = {}
 ---@field language_pad number
 ---@field disable string[]
 ---@field disable_background boolean|string[]
+---@field background_inset integer
 ---@field width render.md.code.Width
 ---@field left_margin number
 ---@field left_pad number
@@ -478,6 +479,8 @@ M.code.default = {
     -- Use a boolean to make behavior apply to all languages.
     -- Borders above & below blocks will continue to be rendered.
     disable_background = { 'diff' },
+    -- Number of lines from start/end to skip rendering background.
+    background_inset = 1,
     -- Width of the code block background.
     -- | block | width of the code block  |
     -- | full  | full width of the window |
@@ -559,6 +562,7 @@ function M.code.schema()
         disable_background = {
             union = { { list = { type = 'string' } }, { type = 'boolean' } },
         },
+        background_inset = { type = 'number' },
         width = { enum = M.code.width },
         left_margin = { type = 'number' },
         left_pad = { type = 'number' },

lua/render-markdown/types.lua

@@ -101,6 +101,7 @@
 ---@field language_pad? number
 ---@field disable? string[]
 ---@field disable_background? boolean|string[]
+---@field background_inset? integer
 ---@field width? render.md.code.Width
 ---@field left_margin? number
 ---@field left_pad? number