Add a language to fix Rust highlights in format-args macros

This is a bit hacky. Injections cannot stack on each other like
highlights because layers can have their own injections. So this new
language `rust-format-args-macro` emulates that. It unconditionally
injects `rust-format-args` into all strings. Rust injects this new
language into known format-args macros like `println!`.

The downside is that this can cause false-positive highlights within
these macros for strings which happen to contain format-args syntax

    println!("Hello, {}!", "{}");
    //               ^ format args syntax
    //                      ^ not format args syntax, but highlighted
    //                        as if it were :(

This false-positive case is expected to be rare.

Injecting this fake language fixes regular non-string highlights in
macro invocations: macro invocations need to inject the entire token
tree and use `injection.include-children` for proper highlighting.

book/src/generated/lang-support.md

@@ -208,6 +208,7 @@
 | ruby | ✓ | ✓ | ✓ | `ruby-lsp`, `solargraph` |
 | rust | ✓ | ✓ | ✓ | `rust-analyzer` |
 | rust-format-args | ✓ |  |  |  |
+| rust-format-args-macro | ✓ | ✓ | ✓ |  |
 | sage | ✓ | ✓ |  |  |
 | scala | ✓ | ✓ | ✓ | `metals` |
 | scheme | ✓ |  | ✓ |  |

languages.toml

@@ -4445,6 +4445,12 @@ injection-regex = "rust-format-args"
 name = "rust-format-args"
 source = { git = "https://github.com/nik-rev/tree-sitter-rust-format-args", rev = "84ffe550e261cf5ea40a0ec31849ba2443bae99f" }
 
+[[language]]
+name = "rust-format-args-macro"
+scope = "source.rust-format-args-macro"
+file-types = []
+grammar = "rust"
+
 [[language]]
 name = "clarity"
 scope = "source.clar"

runtime/queries/rust-format-args-macro/highlights.scm

@@ -0,0 +1 @@
+; inherits: rust

runtime/queries/rust-format-args-macro/indents.scm

@@ -0,0 +1 @@
+; inherits: rust

runtime/queries/rust-format-args-macro/injections.scm

@@ -0,0 +1,13 @@
+; inherits: rust
+
+; HACK: This language is the same as Rust but all strings are injected
+; with rust-format-args. Rust injects this into known macros which use
+; the format args syntax. This can cause false-positive highlights but
+; those are expected to be rare.
+
+([
+   (string_literal (string_content) @injection.content)
+   (raw_string_literal (string_content) @injection.content)
+ ]
+ (#set! injection.language "rust-format-args")
+ (#set! injection.include-children))

runtime/queries/rust-format-args-macro/locals.scm

@@ -0,0 +1 @@
+; inherits: rust

runtime/queries/rust-format-args-macro/textobjects.scm

@@ -0,0 +1 @@
+; inherits: rust

runtime/queries/rust/injections.scm

@@ -103,8 +103,6 @@
 ; the `format_args!` syntax.
 ;
 ; This language is injected into a hard-coded set of macros.
-
-; 1st argument is `format_args!`
 (
   (macro_invocation
     macro:
@@ -113,13 +111,11 @@
           name: (_) @_macro_name)
         (identifier) @_macro_name
       ]
-    (token_tree . [
+    (token_tree) @injection.content
-        (string_literal (string_content) @injection.content)
-        (raw_string_literal (string_content) @injection.content)
-      ]
-    )
   )
   (#any-of? @_macro_name
+    ; 1st argument is `format_args!`
+
     ; std
     "print" "println" "eprint" "eprintln"
     "format" "format_args" "todo" "panic"
@@ -140,63 +136,22 @@
     "eyre"
     ; miette
     "miette"
-  )
-  (#set! injection.language "rust-format-args")
-  (#set! injection.include-children)
-)
 
     ; 2nd argument is `format_args!`
-(
+
-  (macro_invocation
-    macro:
-      [
-        (scoped_identifier
-          name: (_) @_macro_name)
-        (identifier) @_macro_name
-      ]
-    (token_tree
-      . (_)
-      . [
-        (string_literal (string_content) @injection.content)
-        (raw_string_literal (string_content) @injection.content)
-      ]
-    )
-  )
-  (#any-of? @_macro_name
     ; std
     "write" "writeln" "assert" "debug_assert"
     ; defmt
     "expect" "unwrap"
     ; ratatui
     "span"
-  )
-  (#set! injection.language "rust-format-args")
-  (#set! injection.include-children)
-)
 
     ; 3rd argument is `format_args!`
-(
+
-  (macro_invocation
-    macro:
-      [
-        (scoped_identifier
-          name: (_) @_macro_name)
-        (identifier) @_macro_name
-      ]
-    (token_tree
-      . (_)
-      . (_)
-      . [
-        (string_literal (string_content) @injection.content)
-        (raw_string_literal (string_content) @injection.content)
-      ]
-    )
-  )
-  (#any-of? @_macro_name
     ; std
     "assert_eq" "debug_assert_eq" "assert_ne" "debug_assert_ne"
   )
-  (#set! injection.language "rust-format-args")
+  (#set! injection.language "rust-format-args-macro")
   (#set! injection.include-children)
 )