Fix API document for Aws::InstanceProfileCredentials#initialize method (#3314)

Author: ybiquitous

gems/aws-sdk-core/lib/aws-sdk-core/instance_profile_credentials.rb

@@ -57,6 +57,9 @@ class TokenExpiredError < RuntimeError; end
 
  # @param [Hash] options
  # @option options [Integer] :retries (1) Number of times to retry when retrieving credentials.
+ # @option options [Numeric, Proc] :backoff By default, failures are retried with exponential back-off, i.e.
+ # `lambda { |num_failures| sleep(1.2 ** num_failures) }`. You can pass a number of seconds to sleep
+ # between failed attempts, or a Proc that accepts the number of failures.
  # @option options [String] :endpoint ('http://169.254.169.254') The IMDS endpoint. This option has precedence
  # over the `:endpoint_mode`.
  # @option options [String] :endpoint_mode ('IPv4') The endpoint mode for the instance metadata service. This is
@@ -67,14 +70,11 @@ class TokenExpiredError < RuntimeError; end
  # @option options [Integer] :port (80)
  # @option options [Float] :http_open_timeout (1)
  # @option options [Float] :http_read_timeout (1)
- # @option options [Numeric, Proc] :delay By default, failures are retried with exponential back-off, i.e.
- # `sleep(1.2 ** num_failures)`. You can pass a number of seconds to sleep between failed attempts, or a Proc
- # that accepts the number of failures.
  # @option options [IO] :http_debug_output (nil) HTTP wire traces are sent to this object.
  # You can specify something like `$stdout`.
- # @option options [Integer] :token_ttl Time-to-Live in seconds for EC2 Metadata Token used for fetching
- # Metadata Profile Credentials, defaults to 21600 seconds.
- # @option options [Callable] :before_refresh Proc called before credentials are refreshed. `before_refresh`
+ # @option options [Integer] :token_ttl (21600) Time-to-Live in seconds for EC2 Metadata Token used for fetching
+ # Metadata Profile Credentials.
+ # @option options [Proc] :before_refresh A Proc called before credentials are refreshed. `:before_refresh`
  # is called with an instance of this object when AWS credentials are required and need to be refreshed.
  def initialize(options = {})
  @backoff = resolve_backoff(options[:backoff])