XInvocation2: Fix documentation for bExact param of getInfoForName

It looks like the documentation for bExact was just an accidental copy
and paste of the aName param. This changes it to explain what it does
based on looking at the code for the implementation.

Change-Id: Ia767064c66b2125193c75da34273a6d4e6035bd8
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/201453
Reviewed-by: Neil Roberts <bpeeluk@yahoo.co.uk>
Tested-by: Jenkins

udkapi/com/sun/star/script/XInvocation2.idl

@@ -45,7 +45,8 @@ published interface XInvocation2: com::sun::star::script::XInvocation
             specifies the name of the method or property
 
         @param bExact
-            specifies the name of the method or property
+            if `TRUE` then `aName` will first be converted to an exact name. See
+            com::sun::star::beans::XExactName for details.
 
         @throws IllegalArgumentException
             if aName is not the name of a supported method or property