Remove unused Foundation imports

Motivation:

A few files unnecesarily import Foundation

Modifications:

Remove unused imports

Result:

Fewer dependencies

Author: glbrntt

Sources/GRPCCodeGen/CodeGenerationRequest.swift

@@ -14,8 +14,6 @@
  * limitations under the License.
  */
 
-import Foundation
-
 /// Describes the services, dependencies and trivia from an IDL file,
 /// and the IDL itself through its specific serializer and deserializer.
 public struct CodeGenerationRequest {

Sources/GRPCCodeGen/Internal/Renderer/TextBasedRenderer.swift

@@ -26,7 +26,6 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
-import Foundation
 
 /// An object for building up a generated file line-by-line.
 ///

Sources/GRPCCodeGen/Internal/Translator/Docs.swift

@@ -14,8 +14,6 @@
  * limitations under the License.
  */
 
-import Foundation
-
 package enum Docs {
   package static func suffix(_ header: String, withDocs footer: String) -> String {
     if footer.isEmpty {
@@ -58,7 +56,9 @@ package enum Docs {
       """
 
     let body = docs.split(separator: "\n").map { line in
-      "/// > " + line.dropFirst(4).trimmingCharacters(in: .whitespaces)
+      var line = "/// > " + line.dropFirst(4)
+      line.trimPrefix(while: { $0.isWhitespace })
+      return String(line.drop(while: { $0.isWhitespace }))
     }.joined(separator: "\n")
 
     return header + "\n" + body

Sources/GRPCCodeGen/Internal/TypeName.swift

@@ -26,7 +26,6 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
-import Foundation
 
 /// A fully-qualified type name that contains the components of the Swift
 /// type name.