Update library documentation

src/lib.rs

@@ -107,15 +107,21 @@
 //!
 //! * `$"SOME_ENV_VAR_NAME"::str` to inject the environment variables `SOME_ENV_VAR_NAME` as the string value.
 //! No additiocal changes are made ot the value.
-//! * `$"SOME_ENV_VAR_NAME"::bool` to inject the environment variables `SOME_ENV_VAR_NAME` as the boolean value.
+//! * `$"SOME_ENV_VAR_NAME"::bool` to inject the environment variable `SOME_ENV_VAR_NAME` as the boolean value.
 //! The value `true` or `yes` or `on` or `1` are converted into `true` otherwise into `false`. 
-//! * `$"SOME_ENV_VAR_NAME"::int` to inject the environment variables `SOME_ENV_VAR_NAME` as the integer value.
+//! * `$"SOME_ENV_VAR_NAME"::int` to inject the environment variable `SOME_ENV_VAR_NAME` as the integer value.
 //! The successfully parsed value is injected as `i32` or `i64`, depending on the format, otherwise `0i32` is injected. 
-//! * `$"SOME_ENV_VAR_NAME"::flt` to inject the environment variables `SOME_ENV_VAR_NAME` as the floating value.
+//! * `$"SOME_ENV_VAR_NAME"::flt` to inject the environment variable `SOME_ENV_VAR_NAME` as the floating value.
 //! The successfully parsed value is injected as `f32` or `f64`, depending on the format, otherwise `0f32` is injected. 
-//!
-//!
-//! **Example**:
+//! * `$"SOME_ENV_VAR_NAME"::auto` or `$"SOME_ENV_VAR_NAME"` to inject the environment variable `SOME_ENV_VAR_NAME`
+//! and resolve the type automatically. Rules of the type auto-resolution: 
+//! - If the value is *True* or *Yes* or *On* then the result type is `boolean True`; 
+//! - If the value is *False* or *No* or *Off* then the result type is `boolean False`; 
+//! - If the value is floating then the result type is `floating`; 
+//! - If the value is integer then the result type is `integer`; 
+//! - Otherwise the result is `string` value. 
+//!
+//!**Example**:
 //!
 //! ```ignore
 //! #!/bin/sh