Fix typos (#538)

.github/CONTRIBUTING.md

@@ -152,7 +152,7 @@ But it's way more comfortable to run it locally and catch avoidable errors befor
 
 - To run the test suite, all you need is a recent [*tox*].
   It will ensure the test suite runs with all dependencies against all Python versions just as it will in our [CI].
-  If you lack some Python versions, you can can always limit the environments like `tox -e py38,py39`, or make it a non-failure using `tox --skip-missing-interpreters`.
+  If you lack some Python versions, you can always limit the environments like `tox -e py38,py39`, or make it a non-failure using `tox --skip-missing-interpreters`.
 
   In that case you should look into [*asdf*](https://asdf-vm.com) or [*pyenv*](https://github.com/pyenv/pyenv), which make it very easy to install many different Python versions in parallel.
 - Write [good test docstrings](https://jml.io/pages/test-docstrings.html).

docs/getting-started.md

@@ -30,7 +30,7 @@ As a result, the simplest possible usage looks like this:
 
 Here, *structlog* takes advantage of its default settings:
 
-- Output is sent to **[standard out](https://en.wikipedia.org/wiki/Standard_out#Standard_output_.28stdout.29)** instead doing nothing.
+- Output is sent to **[standard out](https://en.wikipedia.org/wiki/Standard_out#Standard_output_.28stdout.29)** instead of doing nothing.
 - It **imitates** standard library {mod}`logging`'s **log level names** for familiarity.
   By default, no level-based filtering is done, but it comes with a **very fast [filtering machinery](filtering)**.
 - Like in `logging`, positional arguments are [**interpolated into the message string using %**](https://docs.python.org/3/library/stdtypes.html#old-string-formatting).

src/structlog/twisted.py

@@ -199,7 +199,7 @@ def __call__(  # type: ignore[override]
 @implementer(ILogObserver)
 class PlainFileLogObserver:
     """
-    Write only the the plain message without timestamps or anything else.
+    Write only the plain message without timestamps or anything else.
 
     Great to just print JSON to stdout where you catch it with something like
     runit.