Update cheatsheets

tldr/msgfmt

@@ -8,6 +8,10 @@ source: https://github.com/tldr-pages/tldr.git
 > Compile message catalog to binary format.
 > More information: <https://www.gnu.org/software/gettext/manual/html_node/msgfmt-Invocation.html>.
 
+- Compile a file to `messages.mo`:
+
+`msgfmt {{file.po}}`
+
 - Convert a `.po` file to a `.mo` file:
 
-`msgfmt {{path/to/file.po}} -o {{path/to/file.mo}}`
+`msgfmt {{path/to/file.po}} {{[-o|--output-file]}} {{path/to/file.mo}}`