LibGUI: Explicitly default initialize class members

Author: https://github.com/LucasChollet
Commit: 0bcfbdb072
Pull-request: https://github.com/SerenityOS/serenity/pull/14058
Reviewed-by: https://github.com/MacDue
Reviewed-by: https://github.com/petelliott

Userland/Libraries/LibGUI/TextEditor.h

@@ -373,7 +373,7 @@ private:
     bool m_cursor_line_highlighting { true };
     size_t m_soft_tab_width { 4 };
     int m_horizontal_content_padding { 3 };
-    TextRange m_selection;
+    TextRange m_selection {};
 
     Optional<u32> m_substitution_code_point;
     mutable OwnPtr<Vector<u32>> m_substitution_string_data; // Used to avoid repeated String construction.

Userland/Libraries/LibGUI/TextRange.h

@@ -61,8 +61,8 @@ private:
     TextPosition normalized_start() const { return m_start < m_end ? m_start : m_end; }
     TextPosition normalized_end() const { return m_start < m_end ? m_end : m_start; }
 
-    TextPosition m_start;
+    TextPosition m_start {};
-    TextPosition m_end;
+    TextPosition m_end {};
 };
 
 }