Update Readme to match default SYSTEM behaviour (#452)

README.md

@@ -95,7 +95,7 @@ CPMAddPackage("uri#tag")
 CPMAddPackage("uri@version#tag")
 ```
 
-In the shorthand syntax if the URI is of the form `gh:user/name`, it is interpreted as GitHub URI and converted to `https://github.com/user/name.git`. If the URI is of the form `gl:user/name`, it is interpreted as a [GitLab](https://gitlab.com/explore/) URI and converted to `https://gitlab.com/user/name.git`. If the URI is of the form `bb:user/name`, it is interpreted as a [Bitbucket](https://bitbucket.org/) URI and converted to `https://bitbucket.org/user/name.git`. Otherwise the URI used verbatim as a git URL. All packages added using the shorthand syntax will be added using the [EXCLUDE_FROM_ALL](https://cmake.org/cmake/help/latest/prop_tgt/EXCLUDE_FROM_ALL.html) flag.
+In the shorthand syntax if the URI is of the form `gh:user/name`, it is interpreted as GitHub URI and converted to `https://github.com/user/name.git`. If the URI is of the form `gl:user/name`, it is interpreted as a [GitLab](https://gitlab.com/explore/) URI and converted to `https://gitlab.com/user/name.git`. If the URI is of the form `bb:user/name`, it is interpreted as a [Bitbucket](https://bitbucket.org/) URI and converted to `https://bitbucket.org/user/name.git`. Otherwise the URI used verbatim as a git URL. All packages added using the shorthand syntax will be added using the [EXCLUDE_FROM_ALL](https://cmake.org/cmake/help/latest/prop_tgt/EXCLUDE_FROM_ALL.html) and [SYSTEM](https://cmake.org/cmake/help/latest/prop_tgt/SYSTEM.html#prop_tgt:SYSTEM) flag.
 
 The single-argument syntax also works for URLs: