Change generated code to start function comment with the function name

[alexandear]

This PR changes generated comments for client functions: append WithBody or WithResponse:

Before:

// AddThing request with any body
AddThingWithBody(ctx context.Context, contentType string, body io.Reader, reqEditors ...RequestEditorFn) (*http.Response, error)

// PostBoth request with any body
PostBothWithBodyWithResponse(ctx context.Context, contentType string, body io.Reader, reqEditors ...RequestEditorFn) (*PostBothResponse, error)

After:

// AddThingWithBody request with any body
AddThingWithBody(ctx context.Context, contentType string, body io.Reader, reqEditors ...RequestEditorFn) (*http.Response, error)

// PostBothWithBodyWithResponse request with any body
PostBothWithBodyWithResponse(ctx context.Context, contentType string, body io.Reader, reqEditors ...RequestEditorFn) (*PostBothResponse, error)