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/str_/case/screaming_snake_case.rs

@@ -29,7 +29,7 @@ impl Command for SubCommand {
     }
 
     fn search_terms(&self) -> Vec<&str> {
-        vec!["convert", "style", "snake", "underscore", "convention"]
+        vec!["convert", "style", "underscore", "convention"]
     }
 
     fn run(

crates/nu-command/src/strings/str_/case/snake_case.rs

@@ -29,14 +29,7 @@ impl Command for SubCommand {
     }
 
     fn search_terms(&self) -> Vec<&str> {
-        vec![
-            "convert",
-            "style",
-            "snake",
-            "underscore",
-            "lower",
-            "convention",
-        ]
+        vec!["convert", "style", "underscore", "lower", "convention"]
     }
 
     fn run(

crates/nu-command/src/strings/str_/case/title_case.rs

@@ -30,7 +30,7 @@ impl Command for SubCommand {
     }
 
     fn search_terms(&self) -> Vec<&str> {
-        vec!["convert", "style", "title", "convention"]
+        vec!["convert", "style", "convention"]
     }
 
     fn run(