Snippet support (#72)

To know more about snippet integration, please visit `:h snippet-integration`, or https://github.com/danymat/neogen#snippet-support !

Co-authored-by: danymat <d.danymat@gmail.com>

doc/neogen.txt

@@ -8,6 +8,7 @@ Table of contents:
   Generate annotations.....................................|neogen.generate()|
   Contributing................................................|neogen-develop|
   Changes in neogen plugin..................................|neogen-changelog|
+  Use popular snippet engines............................|snippet-integration|
   Configurations for the template table........|neogen-template-configuration|
   How to create/customize an annotation....................|neogen-annotation|
 
@@ -97,18 +98,24 @@ Neogen provides those defaults, and you can change them to suit your needs
 
       -- Configuration for default languages
       languages = {},
+
+      -- Use a snippet engine to generate annotations.
+      snippet_engine = nil,
   }
 <
 # Notes~
 
 - to configure a language, just add your configurations in the `languages` table.
   For example, for the `lua` lang:
-  >
+>
    languages = {
      lua = { -- Configuration here }
    }
-  <
-  Default configurations for a languages can be found in `lua/neogen/configurations/<you_language>.lua`
+<
+  Default configurations for a languages can be found in `lua/neogen/configurations/<your_language>.lua`
+
+ - To know which snippet engines are supported, take a look at |snippet-integration|.
+   Example: `snippet_engine = "luasnip"`
 
 
 ------------------------------------------------------------------------------
@@ -121,9 +128,15 @@ For example, if you are inside a function, and called `generate({ type = "func"
 Neogen will go until the start of the function and start annotating for you.
 
 Parameters~
-{opts} `(table)` Options to change default behaviour of generation.
- - {opts.type} `(string?, default: "func")` Which type we are trying to use for generating annotations.
+{opts} `(table)` Optional configs to change default behaviour of generation.
+ - {opts.type} `(string, default: "func")` Which type we are trying to use for generating annotations.
    Currently supported: `func`, `class`, `type`, `file`
+ - {opts.return_snippet} `boolean` if true, will return 3 values from the function call.
+ This option is useful if you want to get the snippet to use with a unsupported snippet engine
+ Below are the returned values:
+ - 1: (type: `string[]`) the resulting lsp snippet
+ - 2: (type: `number`) the `row` to insert the annotations
+ - 3: (type: `number`) the `col` to insert the annotations
 
 ------------------------------------------------------------------------------
                                                                 *neogen-develop*
@@ -152,6 +165,10 @@ Here is the current Neogen version:
 
 Note: We will only document `major` and `minor` versions, not `patch` ones.
 
+## 2.3.0~
+  - Added bundled support with snippet engines !
+    Check out |snippet-integration| for basic setup
+    For more information of possible options, check out |neogen.generate()|
 ## 2.2.0~
   ### Python~
     - Add support for `*args` and `**kwargs`
@@ -167,6 +184,22 @@ Note: We will only document `major` and `minor` versions, not `patch` ones.
     with multiple annotation conventions.
 
 
+==============================================================================
+------------------------------------------------------------------------------
+                                                           *snippet-integration*
+                                   `snippet`
+
+To use a snippet engine, pass the option into neogen setup:
+>
+ require('neogen').setup({
+   snippet_engine = "luasnip",
+   ...
+ })
+<
+Some snippet engines come out of the box bundled with neogen:
+- `"luasnip"` (https://github.com/L3MON4D3/LuaSnip)
+
+
 ==============================================================================
 ------------------------------------------------------------------------------
                                                  *neogen-template-configuration*