Merge pull request #56 from dtolnay/cfgdoc

Document `rustversion::cfg!`

Author: dtolnay

README.md

@@ -73,6 +73,11 @@ rustversion = "1.0"
   —<br>
   For conditional inclusion of attributes; analogous to `cfg_attr`.
 
+- <b>`rustversion::cfg!(`</b><i>selector</i><b>`)`</b>
+  —<br>
+  An expression form of any of the above attributes; for example
+  *if rustversion::cfg!(any(stable, beta)) { ... }*.
+
 <br>
 
 ## Use cases

src/lib.rs

@@ -93,6 +93,13 @@
 //!   <code style="display:inline">cfg_attr</code>.
 //!   </p>
 //!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//!   <b><code style="display:inline">rustversion::cfg!(</code></b><i>selector</i><b><code style="display:inline">)</code></b>
+//!   —<br>
+//!   An expression form of any of the above attributes; for example
+//!   <i>if rustversion::cfg!(any(stable, beta)) { ... }</i>.
+//!   </p>
+//!
 //! <br>
 //!
 //! # Use cases