fix: Supply explicit type on forEach block to try preventing compiler crash

[jbelkins]

Issue #

awslabs/aws-sdk-swift#1681

Description of changes

Preview builds are failing (on a compiler crash) while type checking the expression:

        config.httpInterceptorProviders.forEach { provider in
            let i: any ClientRuntime.HttpInterceptor<ListApplicationInstancesInput, ListApplicationInstancesOutput> = provider.create()
            builder.interceptors.add(i)
        }

This PR adds explicit type info to the forEach body, attempting to aid in type checking:

        config.httpInterceptorProviders.forEach { (provider: any ClientRuntime.HttpInterceptorProvider) -> Void in
            let i: any ClientRuntime.HttpInterceptor<ListApplicationInstancesInput, ListApplicationInstancesOutput> = provider.create()
            builder.interceptors.add(i)
        }

Scope

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[jbelkins]

lol Swift can't infer the generic arguments to create because it has nothing to infer from, unless you explicitly give a type for the variable the return value will be assigned to.

[jbelkins]

Cleaned up the multiline write() call while adding the type info to the forEach body block.