WIP: Add a setting to visually redact enviroment variables (#7124)

Release Notes:

- Added bash syntax highlighting to `.env` files. 
- Added a `private_files` setting for configuring which files should be
considered to contain environment variables or other sensitive
information.
- Added a `redact_private_values` setting to add or remove censor bars
over variable values in files matching the `private_files` patterns.
-(internal) added a new `redactions.scm` query to our language support,
allowing different config file formats to indicate where environment
variable values can be identified in the syntax tree, added this query
to `bash`, `json`, `toml`, and `yaml` files.

---------

Co-authored-by: Nathan <nathan@zed.dev>

crates/language/src/syntax_map.rs

@@ -1059,7 +1059,7 @@ impl<'a> SyntaxMapMatches<'a> {
                 .position(|later_layer| key < later_layer.sort_key())
                 .unwrap_or(self.active_layer_count - 1);
             self.layers[0..i].rotate_left(1);
-        } else {
+        } else if self.active_layer_count != 0 {
             self.layers[0..self.active_layer_count].rotate_left(1);
             self.active_layer_count -= 1;
         }