tdf#97179: do not suggest 1-letter custom dictionary words

Fix for the following regression:

Suggestions for all 1- or 2-letter words contain ~all Greek
letters from the commit c4318b8c
(add Greek alphabet to the technical dictionary).

Change-Id: I9356d439debfec34a963edbe5daacde976cc532c
Reviewed-on: https://gerrit.libreoffice.org/22449Reviewed-by: Michael Stahl <mstahl@redhat.com>
Tested-by: Michael Stahl <mstahl@redhat.com>

linguistic/source/spelldta.cxx

@@ -99,7 +99,7 @@ void SearchSimilarText( const OUString &rText, sal_Int16 nLanguage,
                     // remove characters used to determine hyphenation positions
                     aEntryTxt = comphelper::string::remove(pEntries[k]->getDictionaryWord(), '=');
                 }
-                if (!aEntryTxt.isEmpty()  &&  LevDistance( rText, aEntryTxt ) <= 2)
+                if (!aEntryTxt.isEmpty()  &&  aEntryTxt.getLength() > 1  &&  LevDistance( rText, aEntryTxt ) <= 2)
                     rDicListProps.push_back( aEntryTxt );
             }
         }