Typo fix

Author: lorentey

docs/StandardLibraryProgrammersManual.md

@@ -54,7 +54,7 @@ TODO: Should this subsume or link to [AccessControlInStdlib.rst](https://github.
 
     The underscored component need not be the last. For example, `Swift.Dictionary._worble()` is a good name for an internal helper method, but so is `Swift._NativeDictionary.worble()` -- the `_NativeDictionary` type already has the underscore.
 
-    Initializers don't have a dedicated name we can put the underscore on; instead, we add the underscore on the first argument label: `init(_value: Int)`. If the initializer doesn't have any parameter, then we add a dummy parameter of type Void with an underscored label: for example, `UnsafeBufferPointer.init(_empty: ())`.
+    Initializers don't have a dedicated name we can put the underscore on; instead, we add the underscore on the first argument label: `init(_value: Int)`. If the initializer doesn't have any parameters, then we add a dummy parameter of type Void with an underscored label: for example, `UnsafeBufferPointer.init(_empty: ())`.
 
     This rule ensures we don't accidentally clutter the public namespace with `@usableFromInline` things (which could prevent us from choosing the best names for new public API), and it also makes it easy to see at a glance if a piece of stdlib code uses any non-public entities.