chore: remove engine specific completions from documentation

## Details

Using engine specific (nvim-cmp / blink.cmp) completions offers no
benefit compared to the in process LSP method, either than maybe more
control over order. In either case I will likely deprecate these at some
point, for now removing them from the README to avoid more users.

Author: MeanderingProgrammer

README.md

@@ -133,28 +133,11 @@ the relevant setup.
 The recommended way of getting completions from this plugin. Only requires being
 enabled with no additional configuration, assuming you have general LSP completions.
 
-```lua
-require('render-markdown').setup({
-    completions = { lsp = { enabled = true } },
-})
-```
-
-## nvim-cmp
-
-```lua
-local cmp = require('cmp')
-cmp.setup({
-    sources = cmp.config.sources({
-        { name = 'render-markdown' },
-    }),
-})
-```
-
-## blink.cmp
+Works automatically with `nvim-cmp` and `blink.cmp`.
 
 ```lua
 require('render-markdown').setup({
-    completions = { blink = { enabled = true } },
+    completions = { lsp = { enabled = true } },
 })
 ```
 

doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*       For NVIM v0.11.3       Last change: 2025 August 29
+*render-markdown.txt*      For NVIM v0.11.4     Last change: 2025 September 07
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*
@@ -13,8 +13,6 @@ Table of Contents                          *render-markdown-table-of-contents*
 5. Commands                                         |render-markdown-commands|
 6. Completions                                   |render-markdown-completions|
   - in-process lsp                |render-markdown-completions-in-process-lsp|
-  - nvim-cmp                            |render-markdown-completions-nvim-cmp|
-  - blink.cmp                          |render-markdown-completions-blink.cmp|
   - coq_nvim                            |render-markdown-completions-coq_nvim|
 7. Setup                                               |render-markdown-setup|
   - Headings                                  |render-markdown-setup-headings|
@@ -194,30 +192,11 @@ The recommended way of getting completions from this plugin. Only requires
 being enabled with no additional configuration, assuming you have general LSP
 completions.
 
->lua
-    require('render-markdown').setup({
-        completions = { lsp = { enabled = true } },
-    })
-<
-
-
-NVIM-CMP                                *render-markdown-completions-nvim-cmp*
-
->lua
-    local cmp = require('cmp')
-    cmp.setup({
-        sources = cmp.config.sources({
-            { name = 'render-markdown' },
-        }),
-    })
-<
-
-
-BLINK.CMP                              *render-markdown-completions-blink.cmp*
+Works automatically with `nvim-cmp` and `blink.cmp`.
 
 >lua
     require('render-markdown').setup({
-        completions = { blink = { enabled = true } },
+        completions = { lsp = { enabled = true } },
     })
 <
 

lua/render-markdown/integ/blink.lua

@@ -1,5 +1,3 @@
----@module 'blink.cmp'
-
 local source = require('render-markdown.integ.source')
 
 ---@class render.md.source.blink.Config