[haskell-servant][haskell-yesod] fix specialCharReplacements (#16289)

HaskellServantCodegen and HaskellYesodServerCodegen modify
specialCharReplacements by replacing its keys: backslash ("\\") with
"\\\\" and "\"" with "\\\"".

It seems that those replacements were for using the keys in string
literals in the specialChars table in the generated code. However,
modifying the keys causes the substitution of those characters in
field names not to work, making generated code syntactically invalid.

Since the specialChars table has already been removed, we can safely
stop modifying the specialCharReplacements.

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellServantCodegen.java

@@ -114,12 +114,6 @@ public HaskellServantCodegen() {
         specialCharReplacements.put(">", "GreaterThan");
         specialCharReplacements.put("<", "LessThan");
 
-        // backslash and double quote need double the escapement for both Java and Haskell
-        specialCharReplacements.remove("\\");
-        specialCharReplacements.remove("\"");
-        specialCharReplacements.put("\\\\", "Back_Slash");
-        specialCharReplacements.put("\\\"", "Double_Quote");
-
         // set the output folder here
         outputFolder = "generated-code/haskell-servant";
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellYesodServerCodegen.java

@@ -108,12 +108,6 @@ public HaskellYesodServerCodegen() {
         specialCharReplacements.put(">", "GreaterThan");
         specialCharReplacements.put("<", "LessThan");
 
-        // backslash and double quote need double the escapement for both Java and Haskell
-        specialCharReplacements.remove("\\");
-        specialCharReplacements.remove("\"");
-        specialCharReplacements.put("\\\\", "Back_Slash");
-        specialCharReplacements.put("\\\"", "Double_Quote");
-
         outputFolder = "generated-code" + File.separator + "haskell-yesod";
         apiTemplateFiles.put("api.mustache", ".hs");
         apiTestTemplateFiles.put("api_test.mustache", ".hs");