feat!: align standard captures with upstream

Problem: Sharing highlight queries with upstream tree-sitter and
Helix is difficult.

Solution: Where reasonable, use capture names in tree-sitter's standard
list or Helix's Atom-style hierarchy.

Specifically:

* tree-sitter "standard capture names"
  (https://github.com/tree-sitter/tree-sitter/blob/3f44b896852eb7daaa6df4fb778c9bb52c70c815/highlight/src/lib.rs#L20-L72):

  - `@parameter` -> `@variable.parameter`
  - `@field` -> `@variable.member`
  - `@namespace` -> `@module`
  - `@float` -> `@number.float`
  - `@symbol` -> `@string.special.symbol`
  - `@string.regex` -> `@string.regexp`
  - `@text.*` -> `@markup.*` (`strong`, `italic`, `link`, `strikethrough`; with exceptions; see below)
  - `@text.title` -> `@markup.heading`
  - `@text.literal` -> `@markup.raw`
  - `@text.reference` -> `@markup.link`
  - `@text.uri` -> `@markup.link.url` (in markup links)
  - `@string.special` -> `@markup.link.label` (non-url links)
  - `@punctuation.special` -> `@markup.list` (markdown lists only; move subitems from `@text.todo`)

* Helix captures
  (https://docs.helix-editor.com/master/themes.html#syntax-highlighting):

  - `@method` -> `@function.method`
  - `@method.call` -> `@function.method.call`
  - `@text.{todo,warning,note,danger}` -> `@comment.{error,warning,hint,info,todo}`
  - `@text.diff.{add,delete,}` -> `@diff.{plus,minus,delta}`
  - `@text.uri` -> `@string.special.url` (outside markup)
  - `@preproc` -> `@keyword.directive`
  - `@define` -> `@keyword.directive`(`.define`?)
  - `@storageclass` -> `@keyword.storage`
  - `@conditional` -> `@keyword.conditional`
  - `@debug` -> `@keyword.debug`
  - `@exception` -> `@keyword.exception`
  - `@include` -> `@keyword.import`
  - `@repeat` -> `@keyword.repeat`

* cleanup

  - remove some redundant `@conceal` (but still allow it for conceal-only patterns)
  - remove obsolete `@error` (syntax linting is out of scope for this repo)
  - sort, cleanup capture list in `CONTRIBUTING.md`

1 files changed, 13 insertions, 12 deletions

diff --git a/queries/nix/highlights.scm b/queries/nix/highlights.scm
index 97e5303ba..0f6caf4e2 100644
--- a/queries/nix/highlights.scm
+++ b/queries/nix/highlights.scm
@@ -15,8 +15,8 @@
 
 ; exceptions
 (variable_expression
-  name: (identifier) @exception
-  (#any-of? @exception "abort" "throw")
+  name: (identifier) @keyword.exception
+  (#any-of? @keyword.exception "abort" "throw")
   (#set! "priority" 101))
 
 ; if/then/else
@@ -24,7 +24,7 @@
   "if"
   "then"
   "else"
-] @conditional
+] @keyword.conditional
 
 ; field access default (`a.b or c`)
 "or" @keyword.operator
@@ -37,7 +37,8 @@
   (#set! "priority" 99)) @string
 
 ; paths and URLs
-[ (path_expression) (hpath_expression) (spath_expression) (uri_expression) ] @string.special
+[ (path_expression) (hpath_expression) (spath_expression) ] @string.special.path
+(uri_expression) @string.special.url
 
 ; escape sequences
 (escape_sequence) @string.escape
@@ -61,7 +62,7 @@
 
 ; `?` in `{ x ? y }:`, used to set defaults for named function arguments
 (formal
-  name: (identifier) @parameter
+  name: (identifier) @variable.parameter
   "?"? @operator)
 
 ; `...` in `{ ... }`, used to ignore unknown named function arguments (see above)
@@ -70,7 +71,7 @@
 ; universal is the parameter of the function expression
 ; `:` in `x: y`, used to separate function argument from body (see above)
 (function_expression
-  universal: (identifier) @parameter
+  universal: (identifier) @variable.parameter
   ":" @punctuation.special)
 
 ; function calls
@@ -82,8 +83,8 @@
 (variable_expression) @variable
 
 (variable_expression
-  name: (identifier) @include
-  (#eq? @include "import"))
+  name: (identifier) @keyword.import
+  (#eq? @keyword.import "import"))
 
 (variable_expression
   name: (identifier) @boolean
@@ -115,11 +116,11 @@
 
 (select_expression
   expression: (_) @_expr
-  attrpath: (attrpath attr: (identifier) @field)
+  attrpath: (attrpath attr: (identifier) @variable.member)
   (#not-eq? @_expr "builtins")
 )
-(attrset_expression (binding_set (binding . (attrpath (identifier) @field))))
-(rec_attrset_expression (binding_set (binding . (attrpath (identifier) @field))))
+(attrset_expression (binding_set (binding . (attrpath (identifier) @variable.member))))
+(rec_attrset_expression (binding_set (binding . (attrpath (identifier) @variable.member))))
 
 ; function definition
 (binding 
@@ -142,5 +143,5 @@
 [
   (unary_expression "-" (float_expression))
   (float_expression)
-] @float
+] @number.float