Typo fix for partial constructors in C# 14

Author: breyed

docs/csharp/programming-guide/classes-and-structs/constructors.md

@@ -62,7 +62,7 @@ A class can also have **both** an Instance and Static constructor defined, and t
 
 ## Partial constructors
 
-Beginning with C# 14, you can declare *partial constructors* in a partial class or struct. Any partial constructor must have a *defining declaration* and an *implementing declaration*. The signatures of the declaring and implementing partial constructors must match according to the rules of [partial members](./partial-classes-and-methods.md#partial-members). The defining declaration of the partial constructor can't use the `: base()` or `: this()` constructor initializer. You add any constructor initializer must be added on the implementing declaration.
+Beginning with C# 14, you can declare *partial constructors* in a partial class or struct. Any partial constructor must have a *defining declaration* and an *implementing declaration*. The signatures of the declaring and implementing partial constructors must match according to the rules of [partial members](./partial-classes-and-methods.md#partial-members). The defining declaration of the partial constructor can't use the `: base()` or `: this()` constructor initializer. Any constructor initializer must be added on the implementing declaration.
 
 ## See also