SDBL: unify &/name colouring of query parameters + accept keyword-shaped names

Two related fixes for query parameters like '&НачалоПериода':

1. Grammar — the old 'Parameter { Ampersand Identifier }' rule rejected
   any name that the @external specialize hook turned into a SDBL keyword
   (e.g. 'началопериода' matches BEGINOFPERIOD in FuncKw). Real configs
   use such names routinely. Replaced Identifier with an inlined
   'sdblName' alternative that accepts Identifier OR any category-keyword
   term, so the specializer never breaks parameter parsing.

2. styleTags — previously Parameter/Ampersand was t.modifier and
   Parameter/Identifier was t.local(t.variableName), so '&Имя' rendered
   in two different theme colours. Now every possible leaf inside
   Parameter (Ampersand plus every category keyword that may appear as
   the name) shares t.special(t.variableName) so the parameter renders
   as one visual block — verified by inspecting the live demo's spans:
   both '&' and 'НачалоПериода' end up in the same ͼ class.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: nixel2007

src/index.ts

@@ -118,11 +118,15 @@ export const sdblLanguage = sdblParser.configure({
       Identifier: t.variableName,
       Number: t.number,
       StringLit: t.string,
-      // Parameter references (&ИмяПараметра) — tagged as a typed local so
-      // they stand out from regular identifiers; the `&` punctuation gets
-      // the modifier tag so it renders together with the parameter name.
-      "Parameter/Identifier": t.local(t.variableName),
-      "Parameter/Ampersand": t.modifier,
+      // Parameter references (&ИмяПараметра) — the `sdblName` rule is
+      // inlined (lowercase), so its children sit directly under Parameter
+      // in the tree. Both the `&` and every possible inner-leaf token
+      // (Identifier *or* a category-keyword term that the specializer
+      // produced for the name) get the same `t.special(t.variableName)`
+      // tag so the parameter renders as one visual block. We enumerate the
+      // keyword categories because @lezer/highlight resolves at the leaf
+      // level and the global FuncKw / StmtKw / etc. tags would otherwise win.
+      "Parameter/Ampersand Parameter/Identifier Parameter/StmtKw Parameter/OpKw Parameter/FuncKw Parameter/TypeKw Parameter/MdoKw Parameter/VtKw Parameter/FieldKw Parameter/BoolLit Parameter/NullLit Parameter/UndefinedLit": t.special(t.variableName),
       // Punctuation
       "LParen RParen": t.paren,
       // `{...}` configuration blocks — tag the whole group as t.meta so a

src/sdbl.grammar

@@ -49,7 +49,17 @@ ParenGroup { LParen fragment* RParen }
 // pick the whole group out as configuration metadata.
 BraceGroup { LBrace fragment* RBrace }
 
-Parameter { Ampersand Identifier }
+// Parameter name accepts any identifier-shaped token, including ones that
+// the @external specialize hook turns into category keywords (the most
+// common case is `&НачалоПериода` where `началопериода` matches the
+// BEGINOFPERIOD function name in the SDBL keyword table). Without this the
+// parser produces an error token where the keyword sits and the parameter
+// stops being recognised.
+Parameter { Ampersand sdblName }
+sdblName {
+  Identifier | StmtKw | OpKw | FuncKw | TypeKw | MdoKw | VtKw | FieldKw |
+  BoolLit | NullLit | UndefinedLit
+}
 
 AddOp { Plus | Minus }
 MulOp { Mul | Quotient }