Update docs to mention that mp3s are supported.

app/server/ruby/lib/sonicpi/lang/sound.rb

@@ -2114,7 +2114,7 @@ def sample_loaded?(*args)
       doc name:          :sample_loaded?,
           introduced:    Version.new(2,2,0),
           summary:       "Test if sample was pre-loaded",
-          doc:           "Given a path to a `.wav`, `.wave`, `.aif`, `.aiff`, `.ogg`, `.oga` or `.flac` file, returns `true` if the sample has already been loaded.",
+          doc:           "Given a path to a `.wav`, `.wave`, `.aif`, `.aiff`, `.ogg`, `.oga`, `.flac` or `.mp3` file, returns `true` if the sample has already been loaded.",
           args:          [[:path, :string]],
           opts:          nil,
           accepts_block: false,
@@ -2132,7 +2132,7 @@ def load_sample(*args)
       doc name:          :load_sample,
           introduced:    Version.new(2,0,0),
           summary:       "Pre-load first matching sample",
-          doc:           "Given a path to a `.wav`, `.wave`, `.aif`, `.aiff`, `.ogg`, `.oga` or `.flac` file, pre-loads the sample into memory.
+          doc:           "Given a path to a `.wav`, `.wave`, `.aif`, `.aiff`, `.ogg`, `.oga`, `.flac` or `.mp3` file, pre-loads the sample into memory.
 
 You may also specify the same set of source and filter pre-args available to `sample` itself. `load_sample` will then load all matching samples. See `sample`'s docs for more information." ,
           args:          [[:path, :string]],
@@ -2162,7 +2162,7 @@ def load_samples(*args)
       doc name:          :load_samples,
           introduced:    Version.new(2,0,0),
           summary:       "Pre-load all matching samples",
-          doc:           "Given a directory containing multiple `.wav`, `.wave`, `.aif`, `.aiff`, `.ogg`, `.oga` or `.flac` files, pre-loads all the samples into memory.
+          doc:           "Given a directory containing multiple `.wav`, `.wave`, `.aif`, `.aiff`, `.ogg`, `.oga`, `.flac` or `.mp3` files, pre-loads all the samples into memory.
 
  You may also specify the same set of source and filter pre-args available to `sample` itself. `load_sample` will load all matching samples (not just the sample `sample` would play given the same opts) - see `sample`'s docs for more information." ,
           args:          [[:paths, :list]],
@@ -2278,7 +2278,7 @@ def sample_duration(*args)
       doc name:          :sample_duration,
           introduced:    Version.new(2,0,0),
           summary:       "Get duration of sample in beats",
-          doc:           "Given the name of a loaded sample, or a path to a `.wav`, `.wave`, `.aif`, `.aiff`, `.ogg`, `.oga` or `.flac` file returns the length of time in beats that the sample would play for. `sample_duration` understands and accounts for all the opts you can pass to `sample` which have an effect on the playback duration such as `rate:`. The time returned is scaled to the current BPM.
+          doc:           "Given the name of a loaded sample, or a path to a `.wav`, `.wave`, `.aif`, `.aiff`, `.ogg`, `.oga`, `.flac` or `.mp3` file returns the length of time in beats that the sample would play for. `sample_duration` understands and accounts for all the opts you can pass to `sample` which have an effect on the playback duration such as `rate:`. The time returned is scaled to the current BPM.
 
 *Note:* avoid using `sample_duration` to set the sleep time in `live_loop`s, prefer stretching the sample with the `beat_stretch:` opt or changing the BPM instead. See the examples below for details.",
           args:          [[:path, :string]],
@@ -2528,7 +2528,7 @@ def sample(*args, &blk)
       doc name:          :sample,
           introduced:    Version.new(2,0,0),
           summary:       "Trigger sample",
-          doc:           "Play back a recorded sound file (sample). Sonic Pi comes with lots of great samples included (see the section under help) but you can also load and play `.wav`, `.wave`, `.aif`, `.aiff`, `.ogg`, `.oga` or `.flac` files from anywhere on your computer too. To play a built-in sample use the corresponding keyword such as `sample :bd_haus`. To play any file on your computer use a full path such as `sample \"/path/to/sample.wav\"`.
+          doc:           "Play back a recorded sound file (sample). Sonic Pi comes with lots of great samples included (see the section under help) but you can also load and play `.wav`, `.wave`, `.aif`, `.aiff`, `.ogg`, `.oga`, `.flac` or `.mp3` files from anywhere on your computer too. To play a built-in sample use the corresponding keyword such as `sample :bd_haus`. To play any file on your computer use a full path such as `sample \"/path/to/sample.wav\"`.
 
 There are many opts for manipulating the playback. For example, the `rate:` opt affects both the speed and the pitch of the playback. To control the rate of the sample in a pitch-meaningful way take a look at the `rpitch:` opt.
 
@@ -3452,7 +3452,7 @@ def normalise_args!(args_h, defaults={})
 
       # TODO - this method doesn't seem to be used
       def find_sample_with_path(path)
-        ["wav", "wave", "aif", "aiff","flac", "ogg", "oga"].each do |ext|
+        ["wav", "wave", "aif", "aiff","flac", "ogg", "oga", "mp3"].each do |ext|
           full = "#{path}.#{ext}"
           return full if File.exist?(full)
         end

etc/doc/tutorial/03.6-External-Samples.md

@@ -25,7 +25,7 @@ something to consider.
 
 ## Local Samples
 
-So how do you play any arbitrary WAV, AIFF, OGG, OGA or FLAC file on your computer?
+So how do you play any arbitrary WAV, AIFF, OGG, OGA, FLAC or MP3 file on your computer?
 All you need to do is pass the path of that file to `sample`:
 
 ```

etc/doc/tutorial/03.7-Sample-Packs.md

@@ -145,7 +145,7 @@ of potential candidates. A source can take two forms:
 The `sample` fn will first gather all sources and use them to create a
 large list of candidates. This list is constructed by first adding all
 valid paths and then by adding all the valid `.flac`, `.aif`, `.aiff`,
-`.wav`, `.wave` files contained within the directories.
+`.wav`, `.wave`, `.mp3` files contained within the directories.
 
 For example, take a look at the following code: