Fixed the parameters description

Author: bluemurder

Language/Variables/Data Types/String/Functions/charAt.adoc

@@ -34,7 +34,7 @@ string.charAt(n)
 === Parameters
 `string`: a variable of type String
 
-`n`: a variable of type String
+`n`: a variable of type int
 
 
 [float]
@@ -59,4 +59,4 @@ The n'th character of the String.
 [role="example"]
 * #EXAMPLE# link: https://www.arduino.cc/en/Tutorial/BuiltInExamples#strings[Built-in String Tutorials]
 --
-// SEE ALSO SECTION ENDS
+// SEE ALSO SECTION ENDS