Rollup merge of #36589 - jpadkins:option_docs_safety_wording_fix, r=bluss

fixed the safety header/wording in option.rs

Fixes #36581

screenshot of the rendered documentation: http://imgur.com/14kLVrA

r? @steveklabnik

src/libcore/option.rs

@@ -296,16 +296,14 @@ pub fn expect(self, msg: &str) -> T {
 
     /// Moves the value `v` out of the `Option<T>` if it is `Some(v)`.
     ///
-    /// # Panics
-    ///
-    /// Panics if the self value equals `None`.
-    ///
-    /// # Safety note
-    ///
     /// In general, because this function may panic, its use is discouraged.
     /// Instead, prefer to use pattern matching and handle the `None`
     /// case explicitly.
     ///
+    /// # Panics
+    ///
+    /// Panics if the self value equals `None`.
+    ///
     /// # Examples
     ///
     /// ```