fixed rand crate deprecation warning (#510)

src/algorithms/randomness/rand-choose.md

@@ -8,14 +8,13 @@ Randomly generates a string of given length ASCII characters with custom user-de
 extern crate rand;
 
 use rand::seq::SliceRandom;
-use rand::thread_rng;
 
 fn main() {
     const CHARSET: &[u8] =  b"ABCDEFGHIJKLMNOPQRSTUVWXYZ\
     abcdefghijklmnopqrstuvwxyz\
     0123456789)(*&^%$#@!~";
 
-    let mut rng = thread_rng();
+    let mut rng = rand::thread_rng();
     let password: Option<String> = (0..30)
         .map(|_| Some(*CHARSET.choose(&mut rng)? as char))
         .collect();

src/algorithms/randomness/rand-dist.md

@@ -5,7 +5,7 @@
 By default, random numbers have [uniform distribution].
 To generate numbers with other distributions you instantiate a
 distribution, then sample from that distribution using
-[`IndependentSample::ind_sample`] with help of a random-number
+[`Distribution::sample`] with help of a random-number
 generator [`rand::Rng`].
 
 The [distributions available are documented here][rand-distributions]. An example using the

src/algorithms/randomness/rand-range.md

@@ -16,13 +16,14 @@ fn main() {
 }
 ```
 
-[`Range`] can obtain values with [uniform distribution].
+[`Uniform`] can obtain values with [uniform distribution].
 This has the same effect, but may be faster when repeatedly generating numbers
 in the same range.
 
 ```rust
 extern crate rand;
 
+
 use rand::distributions::{Distribution, Uniform};
 
 fn main() {

src/file/dir/modified.md

@@ -4,7 +4,7 @@
 
 Gets the current working directory by calling [`env::current_dir`],
 then for each entries in [`fs::read_dir`], extracts the
-[`DirEntry::path`] and gets the metada via [`fs::Metadata`]. The
+[`DirEntry::path`] and gets the metadata via [`fs::Metadata`]. The
 [`Metadata::modified`] returns the [`SystemTime::elapsed`] time since
 last modification. [`Duration::as_secs`] converts the time to seconds and
 compared with 24 hours (24 * 60 * 60 seconds). [`Metadata::is_file`] filters