Beancount syntax highlighting (#7389)

Release Notes:

- Added syntax highlighting for [Beancount](https://beancount.github.io)

crates/zed/src/languages.rs

@@ -67,6 +67,7 @@ pub fn init(
     };
 
     language("bash", tree_sitter_bash::language(), vec![]);
+    language("beancount", tree_sitter_beancount::language(), vec![]);
     language(
         "c",
         tree_sitter_c::language(),

crates/zed/src/languages/beancount/config.toml

@@ -0,0 +1,3 @@
+name = "Beancount"
+path_suffixes = ["beancount"]
+brackets = [{ start = "\"", end = "\"", close = false, newline = false }]

crates/zed/src/languages/beancount/highlights.scm

@@ -0,0 +1,21 @@
+(comment) @comment
+(headline) @comment
+[
+    (payee)
+    (narration)
+    (string)
+] @string
+
+(number) @number
+(date) @function
+(currency) @constant
+(account) @identifier
+
+[
+    (option)
+    (include)
+    (open)
+    (balance)
+    (pad)
+    (close)
+] @keyword