task: Allow obtaining custom task variables from tree-sitter queries (#11624)

From now on, only top-level captures are treated as runnable tags and
the rest is appended to task context as custom environmental variables
(unless the name is prefixed with _, in which case the capture is
ignored). This is most likely gonna help with Pest-like test runners.



Release Notes:

- N/A

---------

Co-authored-by: Remco <djsmits12@gmail.com>

crates/languages/src/rust/runnables.scm

@@ -1,6 +1,6 @@
 (
-    (attribute_item (attribute) @_attribute
-        (#match? @_attribute ".*test"))
+    (attribute_item (attribute) @attribute
+        (#match? @attribute ".*test"))
     .
     (function_item
         name: (_) @run)