feat: padding character for inline code

## Details

Request: #389

Allows users to set text values for `code.inline_left` &
`code.inline_right` which will be added to the left and right of inline
code blocks. Will be combined with `code.inline_pad`. Example using half
circles:

```lua
require('render-markdown').setup({
    code = { inline_left = '', inline_right = '' },
})
```

Highlight gets created by inverting the padding highlight in a similar
way we do for `thin` code borders.

Minor other change, re-order class definitions to be top down.

Author: MeanderingProgrammer

Diff for: README.md

@@ -447,6 +447,10 @@ require('render-markdown').setup({
         above = '▄',
         -- Used below code blocks for thin border.
         below = '▀',
+        -- Icon to add to the left of inline code.
+        inline_left = '',
+        -- Icon to add to the right of inline code.
+        inline_right = '',
         -- Padding to add to the left & right of inline code.
         inline_pad = 0,
         -- Highlight for code blocks.
@@ -1005,6 +1009,10 @@ require('render-markdown').setup({
         above = '▄',
         -- Used below code blocks for thin border.
         below = '▀',
+        -- Icon to add to the left of inline code.
+        inline_left = '',
+        -- Icon to add to the right of inline code.
+        inline_right = '',
         -- Padding to add to the left & right of inline code.
         inline_pad = 0,
         -- Highlight for code blocks.

Diff for: doc/custom-handlers.md

@@ -12,30 +12,30 @@ needed, and concealing when the cursor enters.
 Each handler must conform to the following interface:
 
 ```lua
----@class (exact) render.md.MarkText
----@field [1] string text
----@field [2] string|string[] highlights
-
----@alias render.md.MarkLine render.md.MarkText[]
+---@class (exact) render.md.Handler
+---@field extends? boolean
+---@field parse fun(ctx: render.md.HandlerContext): render.md.Mark[]
 
----@class render.md.MarkOpts: vim.api.keyset.set_extmark
----@field virt_text? render.md.MarkLine
----@field virt_text_pos? 'eol'|'inline'|'overlay'
----@field virt_lines? render.md.MarkLine[]
+---@class (exact) render.md.HandlerContext
+---@field buf integer
+---@field root TSNode
 
 ---@class (exact) render.md.Mark
 ---@field conceal boolean
 ---@field start_row integer
 ---@field start_col integer
 ---@field opts render.md.MarkOpts
 
----@class (exact) render.md.HandlerContext
----@field buf integer
----@field root TSNode
+---@class render.md.MarkOpts: vim.api.keyset.set_extmark
+---@field virt_text? render.md.MarkLine
+---@field virt_text_pos? 'eol'|'inline'|'overlay'
+---@field virt_lines? render.md.MarkLine[]
 
----@class (exact) render.md.Handler
----@field extends? boolean
----@field parse fun(ctx: render.md.HandlerContext): render.md.Mark[]
+---@alias render.md.MarkLine render.md.MarkText[]
+
+---@class (exact) render.md.MarkText
+---@field [1] string text
+---@field [2] string|string[] highlights
 ```
 
 The `parse` function takes a `ctx` parameter whose fields are:

Diff for: doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*           For 0.11.0          Last change: 2025 April 01
+*render-markdown.txt*           For 0.11.0          Last change: 2025 April 02
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*
@@ -512,6 +512,10 @@ Default Configuration ~
             above = '▄',
             -- Used below code blocks for thin border.
             below = '▀',
+            -- Icon to add to the left of inline code.
+            inline_left = '',
+            -- Icon to add to the right of inline code.
+            inline_right = '',
             -- Padding to add to the left & right of inline code.
             inline_pad = 0,
             -- Highlight for code blocks.
@@ -1064,6 +1068,10 @@ Code Block Configuration ~
             above = '▄',
             -- Used below code blocks for thin border.
             below = '▀',
+            -- Icon to add to the left of inline code.
+            inline_left = '',
+            -- Icon to add to the right of inline code.
+            inline_right = '',
             -- Padding to add to the left & right of inline code.
             inline_pad = 0,
             -- Highlight for code blocks.

Diff for: lua/render-markdown/health.lua

@@ -5,7 +5,7 @@ local state = require('render-markdown.state')
 local M = {}
 
 ---@private
-M.version = '8.2.3'
+M.version = '8.2.4'
 
 function M.check()
     M.start('version')