Merge pull request #2849 from markotoplak/mergedata_doc

Merge data documentation

Author: janezd

doc/visual-programming/source/widgets/data/mergedata.rst

@@ -48,8 +48,7 @@ Data was to be found, the attribute is removed from available merging attributes
    **Append columns from Extra Data** outputs all instances from
    Data appended by matching instances from Extra Data. When no match is found,
    unknown values are appended.
-   **Find matching rows** outputs similar as above,
-   except hen no match is found, instances are excluded.
+   **Find matching rows** outputs only matching instances.
    **Concatenate tables, merge rows** outputs all instances from both inputs,
    even though the match may not be found. In that case unknown values are
    assigned.
@@ -83,14 +82,3 @@ The third type of merging is shown in the next workflow. The output consist of
 both inputs, with unknown values assigned where no match was found.
 
 .. figure:: images/MergeData-Example3.png
-
-Hint
-----
-
-If the two data sets consist of equally-named attributes (other than
-the ones used to perform the merging), Orange will check by default for
-consistency of the values of these attributes and report an error in
-case of non-matching values. In order to avoid the consistency checking,
-make sure that new attributes are created for each data set: you may use the
-'*Columns with the same name in different files represent different
-variables*' option in the :doc:`File <../data/file>` widget for loading the data.