Fix over-eager parsing of plain values

corpus/declarations.txt

@@ -202,3 +202,30 @@ a {
     (block
       (declaration (property_name) (plain_value))
       (declaration (property_name) (plain_value)))))
+
+=======================================
+Comments right after numbers
+=======================================
+
+a {
+	shape-outside: circle(20em/*=*/at 50% 50%);
+	shape-outside: inset(1em, 1em, 1em, 1em);
+}
+
+---
+
+(stylesheet
+  (rule_set
+    (selectors (tag_name))
+    (block
+      (declaration (property_name) (call_expression (function_name) (arguments
+        (integer_value (unit))
+        (comment)
+        (plain_value)
+        (integer_value (unit))
+        (integer_value (unit)))))
+      (declaration (property_name) (call_expression (function_name) (arguments
+        (integer_value (unit))
+        (integer_value (unit))
+        (integer_value (unit))
+        (integer_value (unit))))))))

corpus/statements.txt

@@ -120,7 +120,7 @@ Supports statements
   (supports_statement
     (negated_query (selector_query (pseudo_class_selector
       (class_name)
-      (arguments (plain_value) (plain_value)))))
+      (arguments (tag_name) (tag_name)))))
     (block)))
 
 ==============================

grammar.js

@@ -328,7 +328,7 @@ module.exports = grammar({
       '/'
     )),
 
-    plain_value: $ => /[-_]*[a-zA-Z][^;()\[\]\s]*/
+    plain_value: $ => /[-_]*[a-zA-Z]([^/,;()\[\]\s]|\/[^\*])*/
   }
 })
 

src/grammar.json

@@ -1607,7 +1607,7 @@
     },
     "plain_value": {
       "type": "PATTERN",
-      "value": "[-_]*[a-zA-Z][^;()\\[\\]\\s]*"
+      "value": "[-_]*[a-zA-Z]([^\\/,;()\\[\\]\\s]|\\/[^\\*])*"
     }
   },
   "extras": [