[lldb] Fix po alias by printing fix-its to the console. (#68755)

The `po` alias now matches the behavior of the `expression` command when
the it can apply a Fix-It to an expression.
Modifications

- Add has `m_fixed_expression` to the `CommandObjectDWIMPrint` class a
`protected` member that stores the post Fix-It expression, just like the
`CommandObjectExpression` class.
- Converted messages to present tense.
- Add test cases that confirms a Fix-It for a C++ expression for both
`po` and `expressions`

rdar://115317419

lldb/source/Commands/CommandObjectExpression.cpp

@@ -439,11 +439,11 @@ bool CommandObjectExpression::EvaluateExpression(llvm::StringRef expr,
   ExpressionResults success = target.EvaluateExpression(
       expr, frame, result_valobj_sp, eval_options, &m_fixed_expression);
 
-  // We only tell you about the FixIt if we applied it.  The compiler errors
-  // will suggest the FixIt if it parsed.
+  // Only mention Fix-Its if the expression evaluator applied them.
+  // Compiler errors refer to the final expression after applying Fix-It(s).
   if (!m_fixed_expression.empty() && target.GetEnableNotifyAboutFixIts()) {
-    error_stream.Printf("  Fix-it applied, fixed expression was: \n    %s\n",
-                        m_fixed_expression.c_str());
+    error_stream << "  Evaluated this expression after applying Fix-It(s):\n";
+    error_stream << "    " << m_fixed_expression << "\n";
   }
 
   if (result_valobj_sp) {