rename placepop example to more obvious popup_placeholder

Cargo.toml

@@ -71,18 +71,18 @@ required-features = ["crossterm"]
 name = "modal"
 required-features = ["crossterm"]
 
+[[example]]
+name = "popup_placeholder"
+required-features = ["crossterm"]
+
 [[example]]
 name = "ratatui_minimal"
 required-features = ["ratatui-crossterm"]
 
 [[example]]
-name = "ratatui_placepop"
+name = "ratatui_popup_placeholder"
 required-features = ["ratatui-crossterm"]
 
-[[example]]
-name = "placepop"
-required-features = ["crossterm"]
-
 [[example]]
 name = "ratatui_editor"
 required-features = ["ratatui-crossterm", "search"]