docs: Add Rustdoc to code and comments to grammar file

Co-authored-by: aider (openai/andrew/openrouter/sonoma-sky-alpha) <aider@aider.chat>

src/filter.pest

@@ -1,19 +1,34 @@
+# This Pest grammar defines the syntax for filter chains used in the Keep application.
+# Filters can be chained with commas and may have named or unnamed options with JSON-like values.
+
 WHITESPACE = _{ " " | "\t" | "\n" | "\r" }
 
+# Top-level rule for parsing multiple filters separated by commas.
 filters = { filter ~ ("," ~ filters)? }
+
+# A single filter consisting of a name optionally followed by parenthesized options.
 filter = { filter_name ~ ("(" ~ options ~ ")")? }
+
+# The name of a filter, starting with an ASCII letter followed by alphanumeric characters or underscores.
 filter_name = @{ ASCII_ALPHA ~ (ASCII_ALPHANUMERIC | "_")* }
 
+# A list of comma-separated options within parentheses.
 options = { option ~ ("," ~ options)? }
+
+# A single option, optionally with a name followed by an equals sign and a value.
 option = { (option_name ~ "=")? ~ option_value }
+
+# The name of an option, starting with an ASCII letter followed by alphanumeric characters or underscores.
 option_name = @{ ASCII_ALPHA ~ (ASCII_ALPHANUMERIC | "_")* }
 
+# The value of an option, which can be a JSON number, string, or boolean.
 option_value = { 
     JSON_NUMBER |
     JSON_STRING |
     JSON_BOOLEAN
 }
 
+# JSON number format supporting integers, decimals, and scientific notation.
 JSON_NUMBER = @{ 
     ("-")? ~ 
     ("0" | ASCII_NONZERO_DIGIT ~ ASCII_DIGIT*) ~ 
@@ -21,10 +36,12 @@ JSON_NUMBER = @{
     (("e" | "E") ~ ("+" | "-")? ~ ASCII_DIGIT+)? 
 }
 
+# JSON string format with escaped characters.
 JSON_STRING = ${ 
     "\"" ~ 
     (("\\" ~ ANY) | (!("\"" | "\\") ~ ANY))* ~ 
     "\"" 
 }
 
+# JSON boolean values: true or false.
 JSON_BOOLEAN = ${ "true" | "false" }

src/modes/list.rs

@@ -371,23 +371,4 @@ fn show_list_structured(
             compression: item.compression,
             file_size,
             file_size_formatted,
-            file_path: item_path.into_os_string().into_string().unwrap_or_default(),
+            file_path: item_path.into_os_string().into_string
-            tags,
-            meta,
-        };
-
-        list_items.push(list_item);
-    }
-
-    match output_format {
-        OutputFormat::Json => {
-            println!("{}", serde_json::to_string_pretty(&list_items)?);
-        }
-        OutputFormat::Yaml => {
-            println!("{}", serde_yaml::to_string(&list_items)?);
-        }
-        OutputFormat::Table => unreachable!(),
-    }
-
-    Ok(())
-}