fix a wrong description in doc [ci skip]

doc/texdoc.tex

@@ -499,7 +499,7 @@ \subsection{Fuzzy search}
 input |«keyword»|. The results of the fuzzy search are shown in an info
 message, which can be seen by using the command-line option |-v|.
 
-The default allowance of Levenshtein distance is |5|. You can change this
+The default allowance of Levenshtein distance is |3|. You can change this
 allowance by using the configuration item \ci{fuzzy\_level}. Results of fuzzy
 search could be different among executions if multiple package names have the
 same Levenshtein distance to the input.