Added: Add support for shared day/night theming across termux apps

With this commit, activities will automatically change theme between day/night if `night-mode` `termux.properties` is not set or is set to `system` without requiring app restart.

Dialog theming will be fully added in a later commit and may currently be in an inconsistent state or have crashes.

The `uiMode` has been removed from `configChanges` of `TermuxActivity`, this may cause termux app to restart if samsung DEX mode is changed, if it does, then users should report it so that it can be fixed by re-adding the value and ignoring the change inside `TermuxActivity.onConfigurationChanged()`. The docs don't state if its necessary. Check related pull request #1446.

Running `termux-reload-settings` will also restart `TermuxActivity`, the activity data should be preserved.

termux-shared/src/main/java/com/termux/shared/markdown/MarkdownUtils.java

@@ -17,6 +17,7 @@ import androidx.core.content.ContextCompat;
 
 import com.google.common.base.Strings;
 import com.termux.shared.R;
+import com.termux.shared.theme.ThemeUtils;
 
 import org.commonmark.ext.gfm.strikethrough.Strikethrough;
 import org.commonmark.node.BlockQuote;
@@ -152,11 +153,14 @@ public class MarkdownUtils {
 
                 @Override
                 public void configureSpansFactory(@NonNull MarkwonSpansFactory.Builder builder) {
-                    builder
-                        // set color for inline code
-                        .setFactory(Code.class, (configuration, props) -> new Object[]{
-                            new BackgroundColorSpan(ContextCompat.getColor(context, R.color.background_markdown_code_inline)),
-                        });
+                    // Do not change color for night themes
+                    if (!ThemeUtils.isNightModeEnabled(context)) {
+                        builder
+                            // set color for inline code
+                            .setFactory(Code.class, (configuration, props) -> new Object[]{
+                                new BackgroundColorSpan(ContextCompat.getColor(context, R.color.background_markdown_code_inline)),
+                            });
+                    }
                 }
             })
             .build();