Allow setting event names in macros.

tracing/src/lib.rs

@@ -214,7 +214,7 @@
 //! ### Configuring Attributes
 //!
 //! Both macros require a [`Level`] specifying the verbosity of the span or
-//! event. Optionally, the [target] and [parent span] may be overridden. If the
+//! event. Optionally, the name, [target] and [parent span] may be overridden. If the
 //! target and parent span are not overridden, they will default to the
 //! module path where the macro was invoked and the current span (as determined
 //! by the collector), respectively.
@@ -237,7 +237,16 @@
 //! ```
 //!
 //! The span macros also take a string literal after the level, to set the name
-//! of the span.
+//! of the span (as above).  In the case of the event macros, the name of the event can
+//! be overridden (the default is `event file:line`) using the `name:` specifier.
+//! 
+//! ```
+//! # use tracing::{span, event, Level};
+//! # fn main() {
+//! span!(Level::TRACE, "my span");
+//! event!(name: "some_info", Level::INFO, "something has happened!");
+//! # }
+//! ```
 //!
 //! ### Recording Fields
 //!