[AHCTransport] Consistent style for initializing local variables (swift-server#10)

[AHCTransport] Consistent style for initializing local variables ### Motivation Move to a consistent style when initializing local variables, always use `let foo = Foo(...)` vs `let foo: Foo = .init(...)`. ### Modifications Updated all occurrences of the latter to use the former. ### Result Consistent local variable initialization. ### Test Plan All tests passed. Reviewed by: gjcairo, simonjbeaumont Builds: ✔︎ pull request validation (5.8) - Build finished. ✔︎ pull request validation (5.9) - Build finished. ✔︎ pull request validation (nightly) - Build finished. ✔︎ pull request validation (soundness) - Build finished. swift-server#10

Author: czechboy0

Tests/OpenAPIAsyncHTTPClientTests/Test_AsyncHTTPClientTransport.swift

@@ -63,7 +63,7 @@ class Test_AsyncHTTPClientTransport: XCTestCase {
  }
 
  func testConvertResponse() async throws {
- let httpResponse: HTTPClientResponse = .init(
+ let httpResponse = HTTPClientResponse(
  status: .ok,
  headers: [
  "content-type": "application/json"
@@ -83,7 +83,7 @@ class Test_AsyncHTTPClientTransport: XCTestCase {
 
  func testSend() async throws {
  let eventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: 1)
- let httpClient: HTTPClient = .init(
+ let httpClient = HTTPClient(
  eventLoopGroupProvider: .shared(eventLoopGroup),
  configuration: .init()
  )