[typescript-fetch] Fix OpenAPITools#1998: namespace reqs.

Fix OpenAPITools#1998 by namespacing the generated request object types used in the
typescript-fetch client codegen.

Author: jgiles

modules/openapi-generator/src/main/resources/typescript-fetch/apis.mustache

@@ -13,17 +13,23 @@ import {
 {{/imports.0}}
 
 {{#operations}}
-{{#operation}}
-{{#allParams.0}}
-export interface {{operationIdCamelCase}}Request {
-    {{#allParams}}
-    {{paramName}}{{^required}}?{{/required}}: {{#isEnum}}{{{datatypeWithEnum}}}{{/isEnum}}{{^isEnum}}{{{dataType}}}{{#isNullable}} | null{{/isNullable}}{{/isEnum}};
-    {{/allParams}}
-}
+/**
+ * The Requests namespace contains generated request parameter interface declarations.
+ */
+export namespace Requests {
+    {{#operation}}
+    {{#allParams.0}}
+    export interface {{operationIdCamelCase}} {
+        {{#allParams}}
+        {{paramName}}{{^required}}?{{/required}}: {{#isEnum}}{{{datatypeWithEnum}}}{{/isEnum}}{{^isEnum}}{{{dataType}}}{{#isNullable}} | null{{/isNullable}}{{/isEnum}};
+        {{/allParams}}
+    }
 
-{{/allParams.0}}
-{{/operation}}
+    {{/allParams.0}}
+    {{/operation}}
+}
 {{/operations}}
+
 {{#operations}}
 /**
  * {{#description}}{{{description}}}{{/description}}{{^description}}no description{{/description}}
@@ -39,7 +45,7 @@ export class {{classname}} extends runtime.BaseAPI {
      * {{&summary}}
      {{/summary}}
      */
-    async {{nickname}}Raw({{#allParams.0}}requestParameters: {{operationIdCamelCase}}Request{{/allParams.0}}): Promise<runtime.ApiResponse<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>> {
+    async {{nickname}}Raw({{#allParams.0}}requestParameters: Requests.{{operationIdCamelCase}}{{/allParams.0}}): Promise<runtime.ApiResponse<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}>> {
         {{#allParams}}
         {{#required}}
         if (requestParameters.{{paramName}} === null || requestParameters.{{paramName}} === undefined) {
@@ -249,7 +255,7 @@ export class {{classname}} extends runtime.BaseAPI {
     }
     {{/useSingleRequestParameter}}
     {{#useSingleRequestParameter}}
-    async {{nickname}}({{#allParams.0}}requestParameters: {{operationIdCamelCase}}Request{{/allParams.0}}): Promise<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}> {
+    async {{nickname}}({{#allParams.0}}requestParameters: Requests.{{operationIdCamelCase}}{{/allParams.0}}): Promise<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}void{{/returnType}}> {
         {{#returnType}}
         const response = await this.{{nickname}}Raw({{#allParams.0}}requestParameters{{/allParams.0}});
         return await response.value();