TextEditor: Minor cleanups in the FileArgument class

* Remove unnecessary #include statements
* Move it into the TextEditor namespace
* Mark the single-argument constructor explicit
* Use move() to avoid some unnecessary copies

Userland/Applications/TextEditor/FileArgument.cpp

@@ -5,11 +5,11 @@
  */
 
 #include "FileArgument.h"
-#include <AK/Optional.h>
-#include <AK/String.h>
 #include <LibCore/File.h>
 #include <LibRegex/Regex.h>
 
+namespace TextEditor {
+
 FileArgument::FileArgument(String file_argument)
 {
     m_line = {};
@@ -17,7 +17,7 @@ FileArgument::FileArgument(String file_argument)
 
     if (Core::File::exists(file_argument)) {
         // A file exists with the full specified name, don't attempt to parse it.
-        m_filename = file_argument;
+        m_filename = move(file_argument);
         return;
     }
 
@@ -58,3 +58,5 @@ FileArgument::FileArgument(String file_argument)
 FileArgument::~FileArgument()
 {
 }
+
+}

Userland/Applications/TextEditor/FileArgument.h

@@ -6,12 +6,13 @@
 
 #pragma once
 
-#include <AK/Optional.h>
 #include <AK/String.h>
 
+namespace TextEditor {
+
 class FileArgument final {
 public:
-    FileArgument(String);
+    explicit FileArgument(String);
     ~FileArgument();
 
     String filename() { return m_filename; }
@@ -23,3 +24,5 @@ private:
     Optional<size_t> m_line;
     Optional<size_t> m_column;
 };
+
+}