Merge #11871

11871: internal: Move `rust.ungram` into `rust-analyzer/crates/syntax` r=Veykril a=Veykril

This makes updating the grammar a lot simpler for us. Though removing it from ungrammar can't be done without bumping it to 2.0 so I'll leave it in there for the time being.
cc rust-analyzer/ungrammar#47

Co-authored-by: Lukas Wirth <[email protected]>

Author: bors[bot]

crates/syntax/Cargo.toml

@@ -30,7 +30,7 @@ rayon = "1.5.1"
 expect-test = "1.2.2"
 proc-macro2 = "1.0.36"
 quote = "1.0.16"
-ungrammar = "=1.16.1"
+ungrammar = "1.16.1"
 
 test_utils = { path = "../test_utils" }
 sourcegen = { path = "../sourcegen" }