lemmatizer/rules/ichidan: add informal conditionals

lib/util/lemmatizer/rules/ichidan_verbs.dart

@@ -173,6 +173,36 @@ final LemmatizationRule ichidanVerbNegativeConditional =
       wordClass: WordClass.ichidanVerb,
     );
 
+final LemmatizationRule ichidanVerbNegativeConditionalVariant1 =
+    LemmatizationRule.simple(
+      name: 'Ichidan verb - negative conditional form (informal variant)',
+      pattern: 'なきゃ',
+      replacement: 'る',
+      lookAheadBehind: _lookBehinds,
+      validChildClasses: [WordClass.ichidanVerb],
+      wordClass: WordClass.ichidanVerb,
+    );
+
+final LemmatizationRule ichidanVerbNegativeConditionalVariant2 =
+    LemmatizationRule.simple(
+      name: 'Ichidan verb - negative conditional form (informal variant)',
+      pattern: 'なくちゃ',
+      replacement: 'る',
+      lookAheadBehind: _lookBehinds,
+      validChildClasses: [WordClass.ichidanVerb],
+      wordClass: WordClass.ichidanVerb,
+    );
+
+final LemmatizationRule ichidanVerbNegativeConditionalVariant3 =
+    LemmatizationRule.simple(
+      name: 'Ichidan verb - negative conditional form (informal variant)',
+      pattern: 'ないと',
+      replacement: 'る',
+      lookAheadBehind: _lookBehinds,
+      validChildClasses: [WordClass.ichidanVerb],
+      wordClass: WordClass.ichidanVerb,
+    );
+
 final LemmatizationRule ichidanVerbNegativeVolitional =
     LemmatizationRule.simple(
       name: 'Ichidan verb - negative volitional form',
@@ -285,6 +315,9 @@ final List<LemmatizationRule> ichidanVerbLemmatizationRules =
       ichidanVerbNegativePast,
       ichidanVerbNegativeTe,
       ichidanVerbNegativeConditional,
+      ichidanVerbNegativeConditionalVariant1,
+      ichidanVerbNegativeConditionalVariant2,
+      ichidanVerbNegativeConditionalVariant3,
       ichidanVerbNegativeVolitional,
       ichidanVerbNegativePotential,
       ichidanVerbNegativePassive,