Accept pragmas within declare expressions

(_declare_item): accept pragmas

Assert pragmas (and other "executable" pragmas) are specifically allowed
in declare expressions, thanks to a recent AI22-0045. They are accepted
by the latest GNAT compilers.

Regenerate grammar using tree-sitter-linux-x64-0.20.7; add test.

grammar.js

@@ -685,6 +685,7 @@ module.exports = grammar({
       _declare_item: $ => choice(
          $.object_declaration,
          $.object_renaming_declaration,
+         $.pragma_g,
       ),
       quantifier: $ => choice(
          reservedWord('all'),

src/grammar.json

@@ -3456,6 +3456,10 @@
         {
           "type": "SYMBOL",
           "name": "object_renaming_declaration"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "pragma_g"
         }
       ]
     },

src/node-types.json

@@ -2095,6 +2095,10 @@
         {
           "type": "object_renaming_declaration",
           "named": true
+        },
+        {
+          "type": "pragma_g",
+          "named": true
         }
       ]
     }

test/corpus/pragmas.txt

@@ -88,3 +88,44 @@ end;
                   (term
                     (numeric_literal)))))
             (identifier)))))))
+
+================================================================================
+pragma in declare expression
+================================================================================
+
+package P is
+   X : Integer :=
+      (declare
+         Y : constant Integer := 123;
+         pragma Assert (True);
+       begin
+         Y);
+end;
+
+--------------------------------------------------------------------------------
+
+(compilation
+  (compilation_unit
+    (package_declaration
+      (identifier)
+      (object_declaration
+        (identifier)
+        (identifier)
+        (expression
+          (term
+            (declare_expression
+              (object_declaration
+                (identifier)
+                (identifier)
+                (expression
+                  (term
+                    (numeric_literal))))
+              (pragma_g
+                (identifier)
+                (pragma_argument_association
+                  (expression
+                    (term
+                      (identifier)))))
+              (expression
+                (term
+                  (identifier))))))))))