Keep @modifiers when parsing locales

[madduck]

Locale modifiers ("@variants") are described in the GNU gettext documentation like this:

The ‘@variant’ can denote any kind of characteristics that is not already implied by the language ll and the country CC. […] It can also denote a dialect of the language, …

Wherein Babel previously would discard these, this patch stores the modifier information in the Locale objects, handling string representation accordingly.

Not implemented is the lookup of a meaningful description of modifiers, but instead — for now — an identity mapping is provided.

All tests pass. Furthermore, integration with flask-babel has been verified to work.

Resolves: #946 Signed-off-by: martin f. krafft madduck@madduck.net

[madduck]

@akx Thank you for your time. I addressed most of your comments, and left an open question in the above. Happy to proceed any way, just let me know what you prefer.

[codecov[bot]]

Codecov Report

Merging #947 (83188f0) into master (6bf793a) will decrease coverage by 0.02%. The diff coverage is 93.10%.

@@            Coverage Diff             @@
##           master     #947      +/-   ##
==========================================
- Coverage   90.91%   90.89%   -0.02%     
==========================================
  Files          25       25              
  Lines        4327     4340      +13     
==========================================
+ Hits         3934     3945      +11     
- Misses        393      395       +2     

Impacted Files	Coverage Δ
babel/core.py	96.31% <93.10%> (-0.45%)	:arrow_down:

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[madduck]

Sorry for the failing tests, was due to the 4/5 tuple return depending on modifier==None. I am not actually very sure it's a good idea, but I see your point. Fixed now.