fix(study): pinyin of names and sayings is typed and checked right

CC-CEDICT capitalises names, so their readings start with a capital vowel
with its tone mark (欧洲 Ōu zhōu, 澳门 Ào mén, 俄语 É yǔ), which the test
for pinyin didn't know: those words were never typed. It now reads the
reading in lower case.

CC-CEDICT also keeps a saying's comma, written between spaces (bù pà màn ,
jiù pà zhàn), and the comma split the reading into two readings, so typing
the whole saying was wrong and half of it right. A comma with a space
before it now stays part of the reading, and commas count for nothing when
readings are compared; a comma written straight after a reading (xíng,
háng) still separates readings.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

halkyon_learn_flutter/test/core/chinese/pinyin_input_test.dart

@@ -27,6 +27,17 @@ void main() {
     expect(givenPinyin('xíng').contains(pinyinKey('xing1')), isFalse);
   });
 
+  test("a saying's comma is part of its reading, as CC-CEDICT writes it "
+      'between spaces; a comma after a reading separates readings', () {
+    final saying = givenPinyin('bù pà màn , jiù pà zhàn');
+
+    expect(saying.contains(pinyinKey('bu4 pa4 man4 jiu4 pa4 zhan4')), isTrue);
+    expect(saying.contains(pinyinKey('bu4pa4man4, jiu4pa4zhan4')), isTrue);
+    expect(saying.contains(pinyinKey('bu4 pa4 man4')), isFalse);
+    expect(saying.contains(pinyinKey('jiu4 pa4 zhan4')), isFalse);
+    expect(givenPinyin('xíng，háng'), {'xíng', 'háng'});
+  });
+
   test("pinyin is told from kana and from words' own letters", () {
     expect(isPinyin('xué xí'), isTrue);
     expect(isPinyin('shuō'), isTrue);
@@ -35,6 +46,14 @@ void main() {
     expect(isPinyin(''), isFalse);
   });
 
+  test('a proper noun, capitalised with its tone mark, is pinyin too', () {
+    expect(isPinyin('Ōu zhōu'), isTrue);
+    expect(isPinyin('Ào mén'), isTrue);
+    expect(isPinyin('É yǔ'), isTrue);
+    expect(isPinyin('Lǘ'), isTrue);
+    expect(givenPinyin('Ōu zhōu').contains(pinyinKey('ou1zhou1')), isTrue);
+  });
+
   test('typing turns a syllable and its tone into the marked syllable, the '
       'caret where it was typed', () {
     const formatter = PinyinInputFormatter();