[JITLink] Fix typo in comment. NFC

Author: wangleiat

llvm/include/llvm/ExecutionEngine/JITLink/JITLink.h

@@ -530,7 +530,7 @@ class Symbol {
     return *Base;
   }
 
-  /// Return the addressable that thsi symbol points to.
+  /// Return the addressable that this symbol points to.
   const Addressable &getAddressable() const {
     assert(Base && "Cannot get underlying addressable for null symbol");
     return *Base;