Fixing spelling typo

Documentation/class-libraries.md

@@ -14,7 +14,7 @@ Platform-specific Class Libraries
 
 Platform-specific libraries are bound to a single .NET platform (e.g. .NET Framework on Windows) and can therefore take significant dependencies on a known execution environment. Such an environment will expose a known set of APIs (.NET and OS APIs) and will maintain and expose expected state (e.g. Windows registry). 
 
-Developers who create plaform specific libraries can fully exploit the underlying platform. The libraries will only ever run on that given platform, making platform checks or other forms of conditional code unnecessary (modulo single sourcing code for multiple platforms).
+Developers who create platform specific libraries can fully exploit the underlying platform. The libraries will only ever run on that given platform, making platform checks or other forms of conditional code unnecessary (modulo single sourcing code for multiple platforms).
 
 Platform-specific libraries have been the primary class library type for the .NET Framework. Even as other .NET platforms emerged, platform-specific libraries remained the dominant library type.
 
@@ -47,4 +47,4 @@ The following platforms support .NET Core class libraries:
 Mono Class Libraries
 ====================
 
-Class libraries are supported on Mono, including the three types of libraries described above. Mono has often been seen (correctly) as a cross-platform implementation of the Microsoft .NET Framework. In part, this was because platform-specific .NET Framework libraries could run on the Mono runtime without modification or re-compilation. This characteristic was in place before the creation of portable class libraries, so was an obvious choice to enable binary portability between the .NET Framework and Mono (although it only worked in one direction).
+Class libraries are supported on Mono, including the three types of libraries described above. Mono has often been seen (correctly) as a cross-platform implementation of the Microsoft .NET Framework. In part, this was because platform-specific .NET Framework libraries could run on the Mono runtime without modification or re-compilation. This characteristic was in place before the creation of portable class libraries, so was an obvious choice to enable binary portability between the .NET Framework and Mono (although it only worked in one direction).