Update functions_xls.md

Author: salomegarnier

source/functions_xls.md

@@ -53,10 +53,10 @@ The following functions are used to create, modify, or analyze text strings in X
 | Function | Description |
 |:---------|:------------|
 | `concat()` | Concatenates one or more arguments (separated by commas) into a single string. |
-| `regex(string, expression)` | Returns `True` if the string is an exact and complete match for a <a href="https://support.kobotoolbox.org/restrict_responses.html">regular expression</a>. |
-| `contains(string, substring)` | Returns `True` if the string contains the substring. |
-| `starts-with(string, substring)` | Returns `True` if the string begins with the substring. |
-| `ends-with(string, substring)` | Returns `True` if the string ends with the substring. |
+| `regex(string, expression)` | Returns `TRUE` if the string is an exact and complete match for a <a href="https://support.kobotoolbox.org/restrict_responses.html">regular expression</a>. |
+| `contains(string, substring)` | Returns `TRUE` if the string contains the substring. |
+| `starts-with(string, substring)` | Returns `TRUE` if the string begins with the substring. |
+| `ends-with(string, substring)` | Returns `TRUE` if the string ends with the substring. |
 | `substr(string, start[, end])` | Returns the substring of `string` beginning at the index start and extending to (but not including) index end (or to the termination of `string`, if end is not provided). |
 | `substring-before(string, target)` | Returns the substring of `string` before the first occurrence of the target substring. If the target is not found, or `string` begins with the target substring, then this will return an empty string. |
 | `substring-after(string, target)` | Returns the substring of `string` after the first occurrence of the target substring. If the target is not found this will return an empty string. |