Remove generic from showBottomSheet (#1045)

See https://github.com/flutter/flutter/pull/137791.

lib/codeviewer/code_segments.dart

diff --git a/lib/codeviewer/code_segments.dart b/lib/codeviewer/code_segments.dart
index 0cea5a2..e157a31 100644
--- a/lib/codeviewer/code_segments.dart
+++ b/lib/codeviewer/code_segments.dart
@@ -3606,9 +3606,7 @@
       TextSpan(style: codeStyle.baseStyle, text: '\u000a        '),
       TextSpan(style: codeStyle.punctuationStyle, text: '.'),
       TextSpan(style: codeStyle.baseStyle, text: 'showBottomSheet'),
-      TextSpan(style: codeStyle.punctuationStyle, text: '<'),
-      TextSpan(style: codeStyle.keywordStyle, text: 'void'),
-      TextSpan(style: codeStyle.punctuationStyle, text: '>('),
+      TextSpan(style: codeStyle.punctuationStyle, text: '('),
       TextSpan(style: codeStyle.baseStyle, text: '\u000a          '),
       TextSpan(style: codeStyle.punctuationStyle, text: '('),
       TextSpan(style: codeStyle.baseStyle, text: 'context'),

lib/demos/material/bottom_sheet_demo.dart

diff --git a/lib/demos/material/bottom_sheet_demo.dart b/lib/demos/material/bottom_sheet_demo.dart
index 99d88dd..6faf85d 100644
--- a/lib/demos/material/bottom_sheet_demo.dart
+++ b/lib/demos/material/bottom_sheet_demo.dart
@@ -158,7 +158,7 @@
     });
 
     Scaffold.of(context)
-        .showBottomSheet<void>(
+        .showBottomSheet(
           (context) {
             return _BottomSheetContent();
           },