refactor: Remove G/Z Namespace support

This previously enabled things like `d g g` to work, but we can
fix that instead by not clearing out pending vim state on change.

Either way, it is unnecessary and causes some user-confusion
(zed-industries/community#176), so remove this code for now; and use
comments to organize the file a bit instead.

crates/vim/src/state.rs

@@ -16,16 +16,9 @@ impl Default for Mode {
     }
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Deserialize)]
-pub enum Namespace {
-    G,
-    Z,
-}
-
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Deserialize)]
 pub enum Operator {
     Number(usize),
-    Namespace(Namespace),
     Change,
     Delete,
     Yank,
@@ -126,8 +119,6 @@ impl Operator {
     pub fn id(&self) -> &'static str {
         match self {
             Operator::Number(_) => "n",
-            Operator::Namespace(Namespace::G) => "g",
-            Operator::Namespace(Namespace::Z) => "z",
             Operator::Object { around: false } => "i",
             Operator::Object { around: true } => "a",
             Operator::Change => "c",