Added and updated documentation and tests

Some undocumented functions and methods are now documented and tested.

Some doc tests were modified to become compilable, going from `ignore`
to `no_run`, or runable, going from `no_run` to regular tests.

src/settings/mod.rs

@@ -24,17 +24,17 @@ const RULESET_CURRENT_VERSION: i32 = 1;
 ///
 /// # Example
 ///
-/// ```ignore
-/// # use lang_evolve_core::settings::*;
-/// # use lang_evolve_core::encode_settings;
-/// use std::io::{Error, ErrorKind};
+/// ```no_run
 /// use std::path::Path;
-/// let filetype = utils::get_file_type(Path::new("./path/to/file.json"));
-/// let s = Settings::new();
+/// use lang_evolve_core::utils;
+///
+/// let settings = Settings::new();
+/// let filetype = utils::get_file_type(Path::new("settings.yml"));
+///
 /// let content = match filetype {
-///     utils::SettingsType::Yaml => encode_settings!(serde_yaml, &s).unwrap(),
-///     utils::SettingsType::Json => encode_settings!(serde_json, &s).unwrap(),
-///     _ => panic!("Could not encode settings"),
+///     SettingsType::Yaml => encode_settings!(serde_yaml, &settings),
+///     SettingsType::Json => encode_settings!(serde_json, &settings),
+///     _ => String::from("Error!"),
 /// };
 /// ```
 ///
@@ -64,7 +64,7 @@ macro_rules! encode_settings {
 ///
 /// # Example
 ///
-/// ```ignore
+/// ```no_run
 /// # use lang_evolve_core::decode_settings;
 /// let str = r#"{"version":"1","categories":[],"rules":[]}"#;
 /// let settings = decode_settings!(serde_json, str);
@@ -162,9 +162,15 @@ impl Settings {
     ///
     /// # Example
     ///
-    /// ```no_run
+    /// ```
     /// use std::path::Path;
-    /// use lang_evolve_core::settings::Settings;
+    /// # use lang_evolve_core::settings::Settings;
+    /// # let s = Settings::new();
+    /// # for path in vec!["settings.json", "settings.yaml", "settings.yml"] {
+    /// #     let path = Path::new(path);
+    /// #     s.export(&path).unwrap();
+    /// # }
+    ///
     /// let path_json = Path::new("settings.json");
     /// let _s_json = Settings::import(&path_json).unwrap();
     ///