refactor(parsing): remove old FromStr-based parser implementation

src/meta_commands.rs

@@ -29,16 +29,3 @@ impl std::fmt::Display for MetaCommandParseError {
         }
     }
 }
-
-impl std::str::FromStr for MetaCommand {
-    type Err = MetaCommandParseError;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        match s.trim() {
-            ".exit" => Ok(MetaCommand::Exit),
-            cmd => Err(MetaCommandParseError::Unrecognized {
-                cmd: cmd.to_string(),
-            }),
-        }
-    }
-}