fixed typos in limitations.md

doc/limitations.md

@@ -17,8 +17,8 @@ Please help to improve it by submitting your findings.
 ## ```1/2``` gives ```0.5```
 
 Since mruby does not have ```Bignum```, bigger integers are represented
-by ```Float``` numbers. To enhace interoperability between ```Float```
-and ```Float```, mruby provides ``Float#upto``` and other iterationg
+by ```Float``` numbers. To enhance interoperability between ```Float```
+and ```Float```, mruby provides ``Float#upto``` and other iterating
 methods for ```Float`` class.  As a side effect, ```1/2``` gives ```0.5```
 not ```0```.