Issue #21593: Merge from 3.5

Doc/library/re.rst

@@ -811,8 +811,8 @@ attributes:
 
 .. method:: regex.search(string[, pos[, endpos]])
 
-   Scan through *string* looking for a location where this regular expression
-   produces a match, and return a corresponding :ref:`match object
+   Scan through *string* looking for the first location where this regular
+   expression produces a match, and return a corresponding :ref:`match object
    <match-objects>`.  Return ``None`` if no position in the string matches the
    pattern; note that this is different from finding a zero-length match at some
    point in the string.