Add comment about missing man page / completions, see #1198

README.md

@@ -332,6 +332,9 @@ higher. You can then use `cargo` to build everything:
 cargo install --locked bat
 ```
 
+Note that addition files like the man page or shell completion
+files can not be installed in this way. They will be generated by `cargo` and should be available in the cargo target folder (under `build`).
+
 ## Customization
 
 ### Highlighting theme