inject language based on file extension & shebang (#3970)

* inject language based on file extension

Nodes can now be captured with "injection.filename". If this capture
contains a valid file extension known to Helix, then the content will
be highlighted as that language.

* inject language by shebang

Nodes can now be captured with "injection.shebang". If this capture
contains a valid shebang line known to Helix, then the content will
be highlighted as the language the shebang calls for.

* add documentation for language injection

* nix: fix highlights

The `@` is now highlighted properly on either side of the function arg.

Also, extending the phases with `buildPhase = prev.buildPhase + ''''`
is now highlighted properly.

Fix highlighting of `''$` style escapes (requires tree-sitter-nix bump)

Fix `inherit` highlighting.

* simplify injection_for_match

Split out injection pair logic into its own method to make the overall
flow easier to follow.

Also transform the top-level function into a method on a
HighlightConfiguration.

* markdown: add shebang injection query

1 files changed, 4 insertions, 2 deletions

diff --git a/helix-term/src/ui/markdown.rs b/helix-term/src/ui/markdown.rs
index 87136992..fea3de78 100644
--- a/helix-term/src/ui/markdown.rs
+++ b/helix-term/src/ui/markdown.rs
@@ -9,7 +9,7 @@ use std::sync::Arc;
 use pulldown_cmark::{CodeBlockKind, Event, HeadingLevel, Options, Parser, Tag};
 
 use helix_core::{
-    syntax::{self, HighlightEvent, Syntax},
+    syntax::{self, HighlightEvent, InjectionLanguageMarker, Syntax},
     Rope,
 };
 use helix_view::{
@@ -47,7 +47,9 @@ pub fn highlighted_code_block<'a>(
 
     let rope = Rope::from(text.as_ref());
     let syntax = config_loader
-        .language_configuration_for_injection_string(language)
+        .language_configuration_for_injection_string(&InjectionLanguageMarker::Name(
+            language.into(),
+        ))
         .and_then(|config| config.highlight_config(theme.scopes()))
         .map(|config| Syntax::new(&rope, config, Arc::clone(&config_loader)));