Fix typo in comments

Author: lkb85

lib/SILGen/SILGenConvert.cpp

@@ -190,7 +190,7 @@ ManagedValue
 SILGenFunction::emitPreconditionOptionalHasValue(SILLocation loc,
                                                  ManagedValue optional,
                                                  bool isImplicitUnwrap) {
-  // Generate code to the optional is present, and if not, abort with a message
+  // Generate code to check if the optional is present, and if not, abort with a message
   // (provided by the stdlib).
   SILBasicBlock *contBB = createBasicBlock();
   SILBasicBlock *failBB = createBasicBlock();

lib/Sema/CSStep.h

@@ -39,7 +39,7 @@ class SolverStep;
 class ComponentStep;
 
 /// Represents available states which every
-/// given step could be in during it's lifetime.
+/// given step could be in during its lifetime.
 enum class StepState { Setup, Ready, Running, Suspended, Done };
 
 /// Represents result of the step execution,