Update documents of QLocale::Country

Quoting from https://en.wikipedia.org/wiki/ISO_3166:
"ISO 3166 is a standard published by the International
Organization for Standardization (ISO) that defines
codes for the names of countries, dependent territories,
special areas of geographical interest, and their
principal subdivisions (e.g., provinces or states).
The official name of the standard is Codes for the
representation of names of countries and their subdivisions."

In order to prevent the word "Country" from causing ambiguity, the
document should clearly state that this enumeration refers to a country
or region.

Change-Id: I05543faa4193b3ddaf31d02c670b4b5f46e94389
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

src/corelib/text/qlocale.cpp

@@ -1262,7 +1262,7 @@ QLocale::Script QLocale::script() const
 }
 
 /*!
-    Returns the country of this locale.
+    Returns the country or region of this locale.
 
     \sa language(), script(), countryToString(), bcp47Name()
 */

src/corelib/text/qlocale.qdoc

@@ -460,7 +460,7 @@
 /*!
     \enum QLocale::Country
 
-    This enumerated type is used to specify a country.
+    This enumerated type is used to specify a country or a region.
 
     \value AnyCountry