Fix typo in a test comment (#1810)

Author: mokagio

Simplenote/src/androidTest/java/com/automattic/simplenote/utils/MatchOffsetHighlighterTest.java

@@ -25,7 +25,7 @@ public Object[] buildSpans() {
     };
 
     // Uses the offsets from a SQLite fulltext offset function call to highlight text
-    // matches are a set of 4 integers seperated by a space. The integers are
+    // matches are a set of 4 integers separated by a space. The integers are
     // 1. The column from the full text table
     // 2. The index of the term from the search
     // 3. The index of the start of the match