involving === verb, involved === adjective

Change `involving` to `involved` to now read, `...call for rather involved syntax.`

Author: StevenBlack

src/generics.md

@@ -2,7 +2,7 @@
 
 *Generics* is the topic of generalizing types and functionalities to broader
 cases. This is extremely useful for reducing code duplication in many ways,
-but can call for rather involving syntax. Namely, being generic requires 
+but can call for rather involved syntax. Namely, being generic requires 
 taking great care to specify over which types a generic type 
 is actually considered valid. The simplest and most common use of generics 
 is for type parameters.