ebook-convert: update path to files in examples (#8885)

pages.it/common/ebook-convert.md

@@ -6,4 +6,4 @@
 
 - Converti un e-book in un altro formato:
 
-`ebook-convert {{originale}} {{convertito}}`
+`ebook-convert {{percorso/al/file_input}} {{file_output}}`

pages/common/ebook-convert.md

@@ -6,8 +6,8 @@
 
 - Convert an e-book into another format:
 
-`ebook-convert {{source}} {{destination}}`
+`ebook-convert {{path/to/input_file}} {{output_file}}`
 
 - Convert Markdown or HTML to e-book with TOC, title and author:
 
-`ebook-convert {{source}} {{destination}} --level1-toc="//h:h1" --level2-toc="//h:h2" --level3-toc="//h:h3" --title={{title}} --authors={{author}}`
+`ebook-convert {{path/to/input_file}} {{output_file}} --level1-toc="//h:h1" --level2-toc="//h:h2" --level3-toc="//h:h3" --title={{title}} --authors={{author}}`