Update docs for open and decode command, regenerate all docs (#4815)

* Update docs for open and decode command, regenerate all docs

* Update open.rs

* Update open.md

Co-authored-by: JT <547158+jntrnr@users.noreply.github.com>

crates/nu-command/src/filesystem/open.rs

@@ -20,7 +20,7 @@ impl Command for Open {
     }
 
     fn usage(&self) -> &str {
-        "Opens a file."
+        "Load a file into a cell, converting to table if possible (avoid by appending '--raw')."
     }
 
     fn signature(&self) -> nu_protocol::Signature {
@@ -172,6 +172,11 @@ impl Command for Open {
                 example: "echo 'myfile.txt' | open",
                 result: None,
             },
+            Example {
+                description: "Open a file, and decode it by the specified encoding",
+                example: "open myfile.txt --raw | decode utf-8",
+                result: None,
+            },
         ]
     }
 }

crates/nu-command/src/strings/decode.rs

@@ -25,6 +25,14 @@ impl Command for Decode {
             .category(Category::Strings)
     }
 
+    fn extra_usage(&self) -> &str {
+        r#"Multiple encodings are supported, here is an example of a few:
+big5, euc-jp, euc-kr, gbk, iso-8859-1, utf-16, cp1252, latin5
+
+For a more complete list of encodings please refer to the encoding_rs
+documentation link at https://docs.rs/encoding_rs/0.8.28/encoding_rs/#statics"#
+    }
+
     fn examples(&self) -> Vec<Example> {
         vec![Example {
             description: "Decode the output of an external command",