add event keyword

src/main/kotlin/io/github/facilityapi/intellij/editor/FsdSyntaxHighlighter.kt

@@ -45,6 +45,7 @@ class FsdSyntaxHighlighter : SyntaxHighlighterBase() {
             FsdTypes.SERVICE,
             FsdTypes.DATA,
             FsdTypes.METHOD,
+            FsdTypes.EVENT,
             FsdTypes.ENUM,
             FsdTypes.ERRORS,
             FsdTypes.EXTERN,

src/main/kotlin/io/github/facilityapi/intellij/fsd.bnf

@@ -53,6 +53,7 @@ private field_list ::= '{' (comment+ | decorated_field)* '}' { pin=1 }
 request_fields ::= field_list
 response_fields ::= field_list
 method_spec ::= method identifier_declaration request_fields ':' response_fields { pin=1 }
+event_spec ::= event identifier_declaration request_fields ':' response_fields { pin=1 }
 
 data_spec ::= data identifier_declaration field_list { pin=1 }
 

src/main/kotlin/io/github/facilityapi/intellij/lexer/_FsdLexer.flex

@@ -84,6 +84,7 @@ MARKDOWN_TEXT=.+
 
   "extern"                       { yybegin(EXTERN_DECL); return EXTERN; }
   "method"                       { yybegin(METHOD_BODY); return METHOD; }
+  "event"                        { yybegin(METHOD_BODY); return EVENT; }
   "data"                         { yybegin(DATA_BODY); return DATA; }
   "errors"                       { yybegin(LIST_BODY); return ERRORS; }
   "enum"                         { yybegin(LIST_BODY); return ENUM; }