Respect locale when capitalizing

[1ec5]

#158 added a localization in Turkish, which has capitalization rules that differ from the C locale used by String.prototype.toUpperCase(). This change uses String.prototype.toLocaleUpperCase() to respect the instruction language’s capitalization rules.

A number of strings in the Turkish localization are affected because a token appears at the beginning of the string. For example, this change:

diff --git a/test/fixtures/v5/arrive_waypoint/left.json b/test/fixtures/v5/arrive_waypoint/left.json
index 4723017..6e8752c 100644
--- a/test/fixtures/v5/arrive_waypoint/left.json
+++ b/test/fixtures/v5/arrive_waypoint/left.json
@@ -25,7 +25,7 @@
         "zh-Hans": "您已经到达您的第一个目的地，在道路左侧"
     },
     "options": {
-        "legIndex": 0,
-        "legCount": 2
+        "legIndex": 1,
+        "legCount": 3
     }
 }

causes {nth} to be replaced by “ikinci”. When capitalized, the output string now becomes:

İkinci hedefinize ulaştınız, hedefiniz solunuzdadır

rather than this misspelling (which is thus mispronounced):

Ikinci hedefinize ulaştınız, hedefiniz solunuzdadır

/cc @malte777 @allierowan @mcwhittemore

[allierowan]

+1