Add ~const bounds to rust grammar

Author: Veykril

src/tools/rust-analyzer/lib/ungrammar/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "ungrammar"
 description = "A DSL for describing concrete syntax trees"
-version = "1.14.8"
+version = "1.14.9"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/matklad/ungrammar"
 edition = "2018"

src/tools/rust-analyzer/lib/ungrammar/rust.ungram

@@ -573,7 +573,7 @@ TypeBoundList =
 
 TypeBound =
   Lifetime
-| '?'? Type
+| ('?' | '~' 'const')? Type
 
 //************************//
 //        Patterns        //