spelling fix in documentation

modules/tm/README

@@ -838,7 +838,7 @@ t_reply("404", "Not found");
 
    Checks if a transaction exists. Returns a positive value if so,
    negative otherwise. Most likely you will not want to use it, as a
-   typical application of a looku-up is to introduce a new transaction if
+   typical application of a look-up is to introduce a new transaction if
    none was found. However this is safely (atomically) done using
    t_newtran.
 

modules/tm/doc/functions.xml

@@ -320,7 +320,7 @@ t_reply("404", "Not found");
 	<para>
 	    Checks if a transaction exists. Returns a positive value if so,
 	    negative otherwise.  Most likely you will not want to use it, as a
-	    typical application of a looku-up is to introduce a new transaction
+	    typical application of a look-up is to introduce a new transaction
 	    if none was found. However this is safely (atomically) done using
 	    <function>t_newtran</function>.
 	</para>