fix: Commit new doc index to releases (#2034)

Author: jbelkins

AWSSDKSwiftCLI/Sources/AWSSDKSwiftCLI/Commands/AWSSDKSwiftCLI/Subcommands/PrepareRelease.swift

@@ -208,6 +208,7 @@ struct PrepareRelease {
                 "packageDependencies.plist",
                 "Sources/Services",
                 "Sources/Core/AWSSDKForSwift/Documentation.docc/AWSSDKForSwift.md",
+                "Sources/Core/SDKForSwift/Documentation.docc/SDKForSwift.md",
                 "Sources/Core/AWSSDKPartitions/Sources/AWSSDKPartitions/Partitions.swift",
                 "Sources/Core/AWSSDKIdentity/",
             ]

AWSSDKSwiftCLI/Tests/AWSSDKSwiftCLITests/Commands/PrepareReleaseTests.swift

@@ -184,7 +184,7 @@ class PrepareReleaseTests: CLITestCase {
         ProcessRunner.testRunner = runner
         let subject = PrepareRelease.mock(repoType: .awsSdkSwift)
         try! subject.stageFiles()
-        XCTAssertTrue(command.hasSuffix("git add Package.swift Package.version Package.version.next packageDependencies.plist Sources/Services Sources/Core/AWSSDKForSwift/Documentation.docc/AWSSDKForSwift.md Sources/Core/AWSSDKPartitions/Sources/AWSSDKPartitions/Partitions.swift Sources/Core/AWSSDKIdentity/"))
+        XCTAssertTrue(command.hasSuffix("git add Package.swift Package.version Package.version.next packageDependencies.plist Sources/Services Sources/Core/AWSSDKForSwift/Documentation.docc/AWSSDKForSwift.md Sources/Core/SDKForSwift/Documentation.docc/SDKForSwift.md Sources/Core/AWSSDKPartitions/Sources/AWSSDKPartitions/Partitions.swift Sources/Core/AWSSDKIdentity/"))
     }
 
     func testStageFilesForSmithySwift() {