Fix PostCSS VS Code integration (#3454)

src/support.js

@@ -79,9 +79,9 @@ const supportTable = [
     aceMode: "css",
     codemirrorMode: "css",
     codemirrorMimeType: "text/css",
-    extensions: [".css"],
+    extensions: [".css", ".pcss", ".postcss"],
     liguistLanguageId: 50,
-    vscodeLanguageIds: ["css"]
+    vscodeLanguageIds: ["css", "postcss"]
   },
   {
     name: "Less",

tests_integration/__tests__/__snapshots__/support-info.js.snap

@@ -99,6 +99,8 @@ Object {
       "codemirrorMode": "css",
       "extensions": Array [
         ".css",
+        ".pcss",
+        ".postcss",
       ],
       "group": "CSS",
       "liguistLanguageId": 50,
@@ -110,6 +112,7 @@ Object {
       "tmScope": "source.css",
       "vscodeLanguageIds": Array [
         "css",
+        "postcss",
       ],
     },
     Object {
@@ -461,9 +464,9 @@ exports[`CLI --support-info (stdout) 1`] = `
       \\"aceMode\\": \\"css\\",
       \\"codemirrorMode\\": \\"css\\",
       \\"codemirrorMimeType\\": \\"text/css\\",
-      \\"extensions\\": [\\".css\\"],
+      \\"extensions\\": [\\".css\\", \\".pcss\\", \\".postcss\\"],
       \\"liguistLanguageId\\": 50,
-      \\"vscodeLanguageIds\\": [\\"css\\"]
+      \\"vscodeLanguageIds\\": [\\"css\\", \\"postcss\\"]
     },
     {
       \\"name\\": \\"Less\\",