more flexible dealing with custom argument types, allowing _ in custom types. Fixes #936

docs/scarpet/api/Overview.md

@@ -188,7 +188,7 @@ baz(entities) -> // same thing
  ```
 
 It works similarly to the auto command, but arguments get their inferred types based on the argument
-names, looking at the full name, or the suffix after the last `_` that indicates the variable type. For instance, variable named `float` will
+names, looking at the full name, or any suffix when splitting on `_` that indicates the variable type. For instance, variable named `float` will
 be parsed as a floating point number, but it can be named `'first_float'` or `'other_float'` as well. Any variable that is not
 supported, will be parsed as a `'string'` type. 
 
@@ -253,8 +253,14 @@ and less frequently used features, like forks and redirects, used pretty much on
 
 ### Command argument types
 
-There are several default argument types that can be used directly without specifying custom types. Each argument can be 
-customized in the `'arguments'` section of the app config, specifying its base type, via `'type'` that needs
+Argument types differ from actual argument names that the types are the suffixes of the used argument names, when separated with 
+`'_'` symbol. For example argument name `'from_pos'` will be interpreted as a built-in type `'int'` and provided to the command system
+as a name `'from_pos'`, however if you define a custom type `'from_pos'`, your custom type will be used instead. 
+Longer suffixes take priority over shorter prefixes, then user defined suffixes mask build-in prefixes.
+
+There are several default argument types that can be used directly without specifying custom types. 
+
+Each argument can be customized in the `'arguments'` section of the app config, specifying its base type, via `'type'` that needs
 to match any of the built-in types, with a series of optional modifiers. Shared modifiers include:
   * `suggest` - static list of suggestions to show above the command while typing
   * `suggester` - function taking one map argument, indicating current state of attributes in the parsed command