docs: add docs for br translation

Author: pietroalbini

docs/changelog/0.5.rst

@@ -19,6 +19,7 @@ Release description not yet written.
 New features
 ------------
 
+* Added Brazilian Portuguese translation
 * Added ability to override default i18n messages
 
   * New attribute :py:attr:`botogram.Bot.override_i18n`

docs/i18n.rst

@@ -19,6 +19,7 @@ Available translations
 
 The following languages are currently included in the botogram package:
 
+* ``br`` (Brazilian Portuguese)
 * ``en`` (English)
 * ``it`` (Italian)
 
@@ -181,4 +182,4 @@ header to reflect your changes.
 .. _`ISO 639-1 code`: https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes
 
 .. _`Python string interpolation`:
-   https://docs.python.org/2/library/stdtypes.html#string-formatting
+   https://docs.python.org/2/library/stdtypes.html#string-formatting