more whitespace updates

book/chapters/options.md

@@ -264,4 +264,5 @@ There are some additional options that can be specified to modify an option for
 -   `->run_callback_for_default()` will specify that the callback should be executed when a default_val is set. This is set automatically when appropriate though it can be turned on or off and any user specified callback for an option will be executed when the default value for an option is set.
 
 ## Unusual circumstances
-There are a few cases where some things break down in the type system managing options and definitions.  Using the `add_option` method defines a lambda function to extract a default value if required.  In most cases this either straightforward or a failure is detected automatically and handled.  But in a few cases a streaming template is available that several layers down may not actually be defined.  The conditions in CLI11 cannot detect this circumstance automatically and will result in compile error.  One specific known case is `boost::optional` if the boost optional_io header is included.  This header defines a template for all boost optional values even if they do no actually have a streaming operator.  For example `boost::optional<std::vector>` does not have a streaming operator but one is detected since it is part of a template.  For these cases a secondary method `app->add_option_no_stream(...)` is provided that bypasses this operation completely and should compile in these cases. 
+There are a few cases where some things break down in the type system managing options and definitions.  Using the `add_option` method defines a lambda function to extract a default value if required.  In most cases this either straightforward or a failure is detected automatically and handled.  But in a few cases a streaming template is available that several layers down may not actually be defined.  The conditions in CLI11 cannot detect this circumstance automatically and will result in compile error.  One specific known case is `boost::optional` if the boost optional_io header is included.  This header defines a template for all boost optional values even if they do no actually have a streaming operator.  For example `boost::optional<std::vector>` does not have a streaming operator but one is detected since it is part of a template.  For these cases a secondary method `app->add_option_no_stream(...)` is provided that bypasses this operation completely and should compile in these cases.
+