support more rescript lang tags

Author: zth

tests/tools_tests/src/docstrings-format/FormatDocstringsTest1.res

@@ -1,7 +1,7 @@
 /**
 This is the first docstring with unformatted ReScript code.
 
-```rescript
+```res example
 let badly_formatted=(x,y)=>{
 let result=x+y
 if result>0{Console.log("positive")}else{Console.log("negative")}
@@ -24,7 +24,7 @@ module Nested = {
 
   But if I add another line here it should be fine.
 
-  ```rescript
+  ```res info
   module UserService={
     let validate=user => user.age>=18 && user.name !== ""
     let getName = user=>user.name

tests/tools_tests/src/expected/FormatDocstringsTest1.res.expected

@@ -1,7 +1,7 @@
 /**
 This is the first docstring with unformatted ReScript code.
 
-```rescript
+```res example
 let badly_formatted = (x, y) => {
   let result = x + y
   if result > 0 {
@@ -28,7 +28,7 @@ module Nested = {
 
   But if I add another line here it should be fine.
 
-  ```rescript
+  ```res info
   module UserService = {
     let validate = user => user.age >= 18 && user.name !== ""
     let getName = user => user.name

tools/src/tools.ml

@@ -726,14 +726,24 @@ module FormatCodeblocks = struct
         in
         mapper.structure mapper ast
   end
+
+  let isResLang lang =
+    match String.lowercase_ascii lang with
+    | "res" | "rescript" | "resi" -> true
+    | lang ->
+      (* Cover ```res example, and similar *)
+      String.starts_with ~prefix:"res " lang
+      || String.starts_with ~prefix:"rescript " lang
+      || String.starts_with ~prefix:"resi " lang
+
   let formatRescriptCodeBlocks content ~transformAssertEqual ~displayFilename
       ~addError ~markdownBlockStartLine =
     (* Detect ReScript code blocks. *)
     let hadCodeBlocks = ref false in
     let block _m = function
       | Cmarkit.Block.Code_block (codeBlock, meta) -> (
         match Cmarkit.Block.Code_block.info_string codeBlock with
-        | Some ((("rescript" | "res"), _) as info_string) ->
+        | Some ((lang, _) as info_string) when isResLang lang ->
           hadCodeBlocks := true;
 
           let currentLine =