build(deps): bump tree-sitter-bash to v0.20.5

runtime/queries/bash/highlights.scm

@@ -43,6 +43,7 @@
   "<<-"
   "<<<"
   ".."
+  "!"
 ] @operator
 
 ; Do *not* spell check strings since they typically have some sort of
@@ -66,6 +67,13 @@
 (command
   argument: "$" @string) ; bare dollar
 
+(concatenation
+  [
+    (simple_expansion)
+    (expansion)
+  ]
+  (word) @string)
+
 [
   "if"
   "then"