CONTRIBUTOR.md: rephrase

CONTRIBUTING.md

@@ -1,18 +1,18 @@
 # Design Overview
 
 ## Fluent Interface Pattern
-The lib is built around a single entry point, the `Stream` class. This is the only import required. This lib must be trivial to use, all the behaviors it exposes should be carefully named and designed to make them self-explanatory as much as possible. A stream declaration should resemble natural language:
+The lib is built around a single entry point, the `Stream` class. This is the only import required. This lib must be trivial to use, all the behaviors it exposes should be carefully named and designed to make them as self-explanatory as possible. A stream declaration should resemble natural language:
 ```python
 events = Stream(events).foreach(print).truncate(when=lambda event: event["year"] > "2023").catch(KeyError)
 ```
 is relatively close to
 > **Stream** the **events** and **for each** one, **print** it, **truncate** the stream **when** an **event**'s **date** is after **2023**, and **catch `KeyError`s** along the way.
 
 ## Composite Pattern
-Applying an operation just performs some arguments validation and returns a new instance of a `Stream` sub-class corresponding to the operation. Defining a stream is basically constructing a composite structure where each node is a `Stream` instance: The above `events` variable holds a `CatchStream[int]` instance, whose `.upstream` attribute points to a `TruncateStream[int]` instance, whose `.upstream` attribute points to a `ForeachStream[int]` instance, whose `.upstream` points to a `Stream[int]` instance. Each node's `.source` attribute points to the same `range(10)`.
+Applying an operation simply performs argument validation and returns a new instance of a `Stream` sub-class corresponding to the operation. Defining a stream is basically constructing a composite structure where each node is a `Stream` instance: The above `events` variable holds a `CatchStream[int]` instance, whose `.upstream` attribute points to a `TruncateStream[int]` instance, whose `.upstream` attribute points to a `ForeachStream[int]` instance, whose `.upstream` points to a `Stream[int]` instance. Each node's `.source` attribute points to the same `range(10)`.
 
 ## Visitor Pattern
-Each node in this composite structure exposes an `.accept` method enabling traversal by a visitor. Both `Stream.__iter__` and `Stream.__repr__` rely on visitors defined in the package `streamable.visitors`.
+Each node in this composite structure exposes an `.accept` method enabling traversal by a visitor. Both `Stream.__iter__` and `Stream.__repr__` rely on visitor classes defined in the `streamable.visitors` package.
 
 ## Decorator Pattern
 A `Stream[T]` both inherits from `Iterable[T]` and holds an `Iterable[T]` as its `.source`: when you instantiate a stream from an iterable you decorate it with a fluent interface.