feat: support quoted extensions in comments

src/reason-parser/reason_declarative_lexer.mll

@@ -824,7 +824,7 @@ and comment buffer firstloc nestedloc = parse
         false
       )
     }
-  | "{" (lowercase* as delim) "|"
+  | "{" ('%' '%'? extattrident blank*)? (lowercase* as delim) "|"
     { store_lexeme buffer lexbuf;
       let stringloc = Location.curr lexbuf in
       let terminated_string = quoted_string buffer delim lexbuf in

test/extensions.t/input.re

@@ -390,3 +390,15 @@ external%foo x: int => int = "caml_prim";
 
 {%%M.foo| <hello>{x} |};
 let x = {%M.foo bar| <hello>{|x|} |bar};
+
+/* Double quotes inside quoted strings inside comments */
+/* {|"|}, and */
+/* [%foo {|"|}], and */
+/* {%foo|"|} should be valid inside comments */
+
+/* Comment delimiters inside quoted strings inside comments: */
+/* {|*)|}, and */
+/* [%foo {bar|*)|bar}], and */
+/* {%foo bar|*)|bar} should be valid inside comments */
+
+

test/extensions.t/run.t

@@ -392,3 +392,13 @@ Format extensions
 
   {%%M.foo | <hello>{x} |};
   let x = {%M.foo bar| <hello>{|x|} |bar};
+
+  /* Double quotes inside quoted strings inside comments */
+  /* {|"|}, and */
+  /* [%foo {|"|}], and */
+  /* {%foo|"|} should be valid inside comments */
+
+  /* Comment delimiters inside quoted strings inside comments: */
+  /* {|*)|}, and */
+  /* [%foo {bar|*)|bar}], and */
+  /* {%foo bar|*)|bar} should be valid inside comments */