docs(fs): add missing docs (#6400)

Author: kt3k

_tools/check_docs.ts

@@ -62,8 +62,17 @@ const ENTRY_POINTS = [
   "../front_matter/mod.ts",
   "../front_matter/unstable_yaml.ts",
   "../fs/mod.ts",
+  "../fs/unstable_chmod.ts",
+  "../fs/unstable_link.ts",
   "../fs/unstable_lstat.ts",
+  "../fs/unstable_make_temp_dir.ts",
+  "../fs/unstable_read_dir.ts",
+  "../fs/unstable_read_file.ts",
+  "../fs/unstable_read_link.ts",
+  "../fs/unstable_real_path.ts",
+  "../fs/unstable_rename.ts",
   "../fs/unstable_stat.ts",
+  "../fs/unstable_symlink.ts",
   "../fs/unstable_types.ts",
   "../html/mod.ts",
   "../html/unstable_is_valid_custom_element_name.ts",

fs/unstable_read_dir.ts

@@ -9,7 +9,7 @@ import type { DirEntry } from "./unstable_types.ts";
  * {@linkcode DirEntry}. The order of entries is not guaranteed.
  *
  * @example Usage
- * ```ts
+ * ```ts no-assert
  * import { readDir } from "@std/fs/unstable-read-dir";
  *
  * for await (const dirEntry of readDir("/")) {
@@ -23,6 +23,9 @@ import type { DirEntry } from "./unstable_types.ts";
  *
  * @tags allow-read
  * @category File System
+ *
+ * @param path The path to the directory to read.
+ * @returns An async iterable of {@linkcode DirEntry}.
  */
 export async function* readDir(path: string | URL): AsyncIterable<DirEntry> {
   if (isDeno) {

fs/unstable_read_file.ts

@@ -11,7 +11,7 @@ import { mapError } from "./_map_error.ts";
  * Requires `allow-read` permission.
  *
  * @example Usage
- * ```ts
+ * ```ts no-assert
  * import { readFile } from "@std/fs/unstable-read-file";
  * const decoder = new TextDecoder("utf-8");
  * const data = await readFile("README.md");
@@ -49,7 +49,7 @@ export async function readFile(
  * Requires `allow-read` permission.
  *
  * @example Usage
- * ```ts
+ * ```ts no-assert
  * import { readFileSync } from "@std/fs/unstable-read-file";
  * const decoder = new TextDecoder("utf-8");
  * const data = readFileSync("README.md");

fs/unstable_symlink.ts

@@ -22,6 +22,7 @@ import type { SymlinkOptions } from "./unstable_types.ts";
  *
  * @param oldpath The path of the resource pointed by the symbolic link.
  * @param newpath The path of the symbolic link.
+ * @param options Options when creating a symbolic link.
  */
 export async function symlink(
   oldpath: string | URL,
@@ -61,6 +62,7 @@ export async function symlink(
  *
  * @param oldpath The path of the resource pointed by the symbolic link.
  * @param newpath The path of the symbolic link.
+ * @param options Options when creating a symbolic link.
  */
 export function symlinkSync(
   oldpath: string | URL,