add deno clean command to site and sidebar (#1428)

Author: philhawksworth

runtime/_data.ts

@@ -58,18 +58,22 @@ export const sidebar = [
             label: "deno bench",
             id: "/runtime/reference/cli/bench/",
           },
-          {
-            label: "deno completions",
-            id: "/runtime/reference/cli/completions/",
-          },
           {
             label: "deno check",
             id: "/runtime/reference/cli/check/",
           },
+          {
+            label: "deno clean",
+            id: "/runtime/reference/cli/clean/",
+          },
           {
             label: "deno compile",
             id: "/runtime/reference/cli/compile/",
           },
+          {
+            label: "deno completions",
+            id: "/runtime/reference/cli/completions/",
+          },
           {
             label: "deno coverage",
             id: "/runtime/reference/cli/coverage/",

runtime/reference/cli/clean.md

@@ -0,0 +1,4 @@
+---
+title: "deno clean"
+command: clean
+---