Fix replace algorithm updating of ranges.

Author: SergioEstevao

Aztec/Classes/Extensions/NSMutableAttributedString+ReplaceOcurrences.swift

@@ -32,17 +32,19 @@ extension NSMutableAttributedString {
 
         assert(!replacementString.contains(stringToFind),
                "Allowing the replacement string to contain the original string would result in a ininite loop.")
-
-        let swiftUTF16Range = string.utf16.range(from: range)
+        let rangeDifference = (replacementString as NSString).length - (stringToFind as NSString).length
+        var swiftUTF16Range = string.utf16.range(from: range)
         var swiftRange = string.range(from: swiftUTF16Range)
-
         while let matchRange = string.range(of: stringToFind, options: [], range: swiftRange, locale: nil) {
             let matchNSRange = string.utf16NSRange(from: matchRange)
 
             replaceCharacters(in: matchNSRange, with: replacementString)
 
             // Since the new string may invalidate the initial swift range, we want to update it.
-            swiftRange = swiftRange.lowerBound ..< string.index(matchRange.lowerBound, offsetBy: replacementString.count)
+            // And because the string that backs the NSAttributeString will change after the replace we need to recalculate the index from scratch
+            let updatedRange = range.extendedRight(by: rangeDifference)
+            swiftUTF16Range = string.utf16.range(from: updatedRange)
+            swiftRange = string.range(from: swiftUTF16Range)
         }
     }
 }