Test command names and search terms for redundancy (#6380)

* Test commands for proper names and search terms

Assert that the `Command.name()` is equal to `Signature.name`

Check that search terms are not just substrings of the command name as
they would not help finding the command.

* Clean up search terms

Remove redundant terms that just replicate the command name.
Try to eliminate substring between search terms, clean up where
necessary.

crates/nu-command/src/strings/split/column.rs

@@ -34,7 +34,7 @@ impl Command for SubCommand {
     }
 
     fn search_terms(&self) -> Vec<&str> {
-        vec!["column", "separate", "divide"]
+        vec!["separate", "divide"]
     }
 
     fn run(

crates/nu-command/src/strings/split/list.rs

@@ -28,7 +28,7 @@ impl Command for SubCommand {
     }
 
     fn search_terms(&self) -> Vec<&str> {
-        vec!["list", "separate", "divide"]
+        vec!["separate", "divide"]
     }
 
     fn run(

crates/nu-command/src/strings/split/row.rs

@@ -34,7 +34,7 @@ impl Command for SubCommand {
     }
 
     fn search_terms(&self) -> Vec<&str> {
-        vec!["row", "separate", "divide"]
+        vec!["separate", "divide"]
     }
 
     fn run(

crates/nu-command/src/strings/split/words.rs

@@ -45,7 +45,7 @@ impl Command for SubCommand {
     }
 
     fn search_terms(&self) -> Vec<&str> {
-        vec!["word", "separate", "divide"]
+        vec!["separate", "divide"]
     }
 
     fn examples(&self) -> Vec<Example> {