Fix small typo

website/source/docs/configuration/interpolation.html.md

@@ -322,7 +322,7 @@ The supported built-in functions are:
       `a_resource_param = ["${split(",", var.CSV_STRING)}"]`.
       Example: `split(",", module.amod.server_ids)`
 
-  * `substr(string, offset, length)` - Extracts a substring from the input string. A negative offset is interpreted as being equivalent to a positive offset measured backwards from the end of the string. A length of `-1` is interpretted as meaning "until the end of the string".
+  * `substr(string, offset, length)` - Extracts a substring from the input string. A negative offset is interpreted as being equivalent to a positive offset measured backwards from the end of the string. A length of `-1` is interpreted as meaning "until the end of the string".
 
   * `timestamp()` - Returns a UTC timestamp string in RFC 3339 format. This string will change with every
    invocation of the function, so in order to prevent diffs on every plan & apply, it must be used with the