Allow lazy loading of translations in gettext.

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2018-12-31.13:14:02.336>
labels = ['3.8', 'type-feature', 'library']
title = 'Allow lazy loading of translations in gettext.'
updated_at = <Date 2018-12-31.13:14:02.336>
user = 'https://github.com/s-ball'

bugs.python.org fields:

activity = <Date 2018-12-31.13:14:02.336>
actor = 's-ball'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2018-12-31.13:14:02.336>
creator = 's-ball'
dependencies = []
files = []
hgrepos = []
issue_num = 35628
keywords = []
message_count = 1.0
messages = ['332815']
nosy_count = 1.0
nosy_names = ['s-ball']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue35628'
versions = ['Python 3.8']