[clang][StaticAnalyzer] Fix a typo in comments [NFC]

Author: benshi001

clang/include/clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h

@@ -344,7 +344,7 @@ class GlobalImmutableSpaceRegion : public NonStaticGlobalSpaceRegion {
 };
 
 /// The region containing globals which can be modified by calls to
-/// "internally" defined functions - (for now just) functions other then system
+/// "internally" defined functions - (for now just) functions other than system
 /// calls.
 class GlobalInternalSpaceRegion : public NonStaticGlobalSpaceRegion {
   friend class MemRegionManager;