v.help: add download.txt, so that v help download works too, cleanu…

…p help.v

vlib/v/help/help.v

@@ -68,15 +68,15 @@ fn print_topic_unknown(topic string) {
 }
 
 fn print_known_topics() {
-	mut res := 'Known help topics: '
 	topic_paths := os.walk_ext(help_dir(), '.txt')
-	for i, path in topic_paths {
+	mut res := []string{}
+	for path in topic_paths {
 		topic := os.file_name(path).all_before('.txt')
 		if topic != 'default' {
-			res += topic + if i != topic_paths.len - 1 { ', ' } else { '.' }
+			res << topic
 		}
 	}
-	println(res)
+	println('Known help topics: ${res.sorted()}')
 }
 
 fn get_vexe() string {

vlib/v/help/other/download.txt

@@ -0,0 +1,19 @@
+vdownload 0.0.1
+-----------------------------------------------
+Usage: vdownload [options] URL1 URL2 ...
+
+Description: Download files from http/https servers, given their URLs.
+
+The arguments should be at least 1 in number.
+
+Options:
+  -h, --help                Show this help screen.
+  -t, --target-folder <string>
+                            The target folder, where the file will be stored. It will be created, if it does not exist. Default is current folder.
+  -1, --sha1                Show the SHA1 hash of the downloaded file.
+  -2, --sha256              Show the SHA256 hash of the downloaded file.
+  -c, --continue            Continue on download failures. If you download 5 URLs, and several of them fail, continue without error. False by default.
+  -r, --retries <int>       Number of retries, when an URL fails to download.
+  -d, --delay <float>       Delay in seconds, after each retry.
+  -R, --run                 Run, after the script/program is completely downloaded.
+  -D, --delete-after-run    Delete the downloaded script/program, after it has been run.