feat: add delay keyword to syntax highlighting (#272)

The upcoming Hack `delay` keyword is syntactically identical to `await`.
Add it to the control keyword grammar pattern and include a snapshot test.

Co-authored-by: Claude <svc-devxp-claude@slack-corp.com>

Author: mszabo-wikia

syntaxes/hack.json

@@ -988,7 +988,7 @@
               "name": "keyword.control.php"
             }
           },
-          "match": "\\s*\\b(await|break|c(ase|ontinue)|concurrent|default|do|else|for(each)?|if|nameof|return|switch|use|while)\\b"
+          "match": "\\s*\\b(await|break|c(ase|ontinue)|concurrent|de(fault|lay)|do|else|for(each)?|if|nameof|return|switch|use|while)\\b"
         },
         {
           "begin": "(?i)\\b((?:require|include)(?:_once)?)\\b\\s*",

test/grammar/delay.hack

@@ -0,0 +1,7 @@
+async function gen_foo(): Awaitable<int> {
+  return 1;
+}
+
+async function gen_bar(): Awaitable<void> {
+  $x = delay gen_foo();
+}

test/grammar/delay.hack.snap

@@ -0,0 +1,59 @@
+# SYNTAX TEST "source.hack" "autogenerated snapshot test"
+>async function gen_foo(): Awaitable<int> {
+#^^^^^ source.hack meta.function.php storage.modifier.php
+#     ^ source.hack meta.function.php
+#      ^^^^^^^^ source.hack meta.function.php storage.type.function.php
+#              ^ source.hack meta.function.php
+#               ^^^^^^^ source.hack meta.function.php entity.name.function.php
+#                      ^ source.hack meta.function.php punctuation.definition.parameters.begin.php
+#                       ^ source.hack meta.function.php punctuation.definition.parameters.end.php
+#                        ^ source.hack meta.function.php punctuation.definition.type.php
+#                         ^ source.hack meta.function.php
+#                          ^^^^^^^^^ source.hack meta.function.php support.class.php
+#                                   ^ source.hack meta.function.php
+#                                    ^^^ source.hack meta.function.php support.type.php
+#                                       ^ source.hack meta.function.php
+#                                        ^ source.hack meta.function.php
+#                                         ^ source.hack punctuation.section.scope.begin.php
+>  return 1;
+#^^ source.hack
+#  ^^^^^^ source.hack keyword.control.php
+#        ^ source.hack
+#         ^ source.hack constant.numeric.php
+#          ^ source.hack punctuation.terminator.expression.php
+>}
+#^ source.hack punctuation.section.scope.end.php
+>
+#^ source.hack
+>async function gen_bar(): Awaitable<void> {
+#^^^^^ source.hack meta.function.php storage.modifier.php
+#     ^ source.hack meta.function.php
+#      ^^^^^^^^ source.hack meta.function.php storage.type.function.php
+#              ^ source.hack meta.function.php
+#               ^^^^^^^ source.hack meta.function.php entity.name.function.php
+#                      ^ source.hack meta.function.php punctuation.definition.parameters.begin.php
+#                       ^ source.hack meta.function.php punctuation.definition.parameters.end.php
+#                        ^ source.hack meta.function.php punctuation.definition.type.php
+#                         ^ source.hack meta.function.php
+#                          ^^^^^^^^^ source.hack meta.function.php support.class.php
+#                                   ^ source.hack meta.function.php
+#                                    ^^^^ source.hack meta.function.php support.class.php
+#                                        ^ source.hack meta.function.php
+#                                         ^ source.hack meta.function.php
+#                                          ^ source.hack punctuation.section.scope.begin.php
+>  $x = delay gen_foo();
+#^^ source.hack
+#  ^ source.hack variable.other.php punctuation.definition.variable.php
+#   ^ source.hack variable.other.php
+#    ^ source.hack
+#     ^ source.hack keyword.operator.assignment.php
+#      ^ source.hack
+#       ^^^^^ source.hack keyword.control.php
+#            ^ source.hack
+#             ^^^^^^^ source.hack meta.function-call.php entity.name.function.php
+#                    ^^ source.hack
+#                      ^ source.hack punctuation.terminator.expression.php
+>}
+#^ source.hack punctuation.section.scope.end.php
+>
+#^ source.hack