Use raw strings for quoted code in extensions generator

Author: atifaziz

bld/ExtensionsGenerator/Program.cs

@@ -290,57 +290,62 @@ select Argument(IdentifierName(p.Identifier)),
                         .WithSemicolonToken(ParseToken(";").WithTrailingTrivia(LineFeed))
         }
         into m
-        select (!noClassLead ? $@"
-    /// <summary><c>{m.Name}</c> extension.</summary>
-
-    [GeneratedCode(""{thisAssemblyName.Name}"", ""{thisAssemblyName.Version}"")]" : null) + $@"
-    public static partial class {m.Name}Extension
-    {{
-{string.Join(null, from mo in m.Overloads select mo.ToFullString())}
-    }}";
-
-    var template = $@"
-#region License and Terms
-// MoreLINQ - Extensions to LINQ to Objects
-//
-// Licensed under the Apache License, Version 2.0 (the ""License"");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an ""AS IS"" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-#endregion
-
-// This code was generated by a tool. Any changes made manually will be lost
-// the next time this code is regenerated.
-
-#nullable enable // required for auto-generated sources (see below why)
-
-// > Older code generation strategies may not be nullable aware. Setting the
-// > project-level nullable context to ""enable"" could result in many
-// > warnings that a user is unable to fix. To support this scenario any syntax
-// > tree that is determined to be generated will have its nullable state
-// > implicitly set to ""disable"", regardless of the overall project state.
-//
-// Source: https://github.com/dotnet/roslyn/blob/70e158ba6c2c99bd3c3fc0754af0dbf82a6d353d/docs/features/nullable-reference-types.md#generated-code
-
-#pragma warning disable RS0041 // Public members should not use oblivious types
-
-namespace MoreLinq.Extensions
-{{
-{string.Join("\n", imports)}
-{string.Join("\n", classes)}
-}}
-    ";
+        let classLead = !noClassLead
+            ? $$"""
+
+                    /// <summary><c>{{m.Name}}</c> extension.</summary>
+
+                    [GeneratedCode("{{thisAssemblyName.Name}}", "{{thisAssemblyName.Version}}")]
+                """
+            : null
+        select $$"""
+            {{classLead}}
+                public static partial class {{m.Name}}Extension
+                {
+            {{string.Join(null, from mo in m.Overloads select mo.ToFullString())}}
+                }
+            """;
+
+    var template = $$"""
+        #region License and Terms
+        // MoreLINQ - Extensions to LINQ to Objects
+        //
+        // Licensed under the Apache License, Version 2.0 (the "License");
+        // you may not use this file except in compliance with the License.
+        // You may obtain a copy of the License at
+        //
+        //     http://www.apache.org/licenses/LICENSE-2.0
+        //
+        // Unless required by applicable law or agreed to in writing, software
+        // distributed under the License is distributed on an "AS IS" BASIS,
+        // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+        // See the License for the specific language governing permissions and
+        // limitations under the License.
+        #endregion
+
+        // This code was generated by a tool. Any changes made manually will be lost
+        // the next time this code is regenerated.
+
+        #nullable enable // required for auto-generated sources (see below why)
+
+        // > Older code generation strategies may not be nullable aware. Setting the
+        // > project-level nullable context to "enable" could result in many
+        // > warnings that a user is unable to fix. To support this scenario any syntax
+        // > tree that is determined to be generated will have its nullable state
+        // > implicitly set to "disable", regardless of the overall project state.
+        //
+        // Source: https://github.com/dotnet/roslyn/blob/70e158ba6c2c99bd3c3fc0754af0dbf82a6d353d/docs/features/nullable-reference-types.md#generated-code
+
+        #pragma warning disable RS0041 // Public members should not use oblivious types
+
+        namespace MoreLinq.Extensions
+        {
+        {{string.Join("\n", imports)}}
+        {{string.Join("\n", classes)}}
+        }
+        """;
 
-    Console.WriteLine(template.Trim()
-                              // normalize line endings
-                              .Replace("\r", string.Empty, StringComparison.Ordinal)
+    Console.WriteLine(template.Replace("\r", string.Empty, StringComparison.Ordinal)
                               .Replace("\n", Environment.NewLine, StringComparison.Ordinal));
 }