Merge pull request #2071 from candleindark/enh

[FIX] Remove contradicting sentence and fix typos in `CONTRIBUTING.md`

Author: effigies

CONTRIBUTING.md

@@ -237,13 +237,10 @@ pip install -U pip
 pip install -r requirements.txt
 ```
 
-The first command ensures you are using an up to date version of `pip`,
+The first command ensures you are using an up-to-date version of `pip`,
 and the second command installs all dependencies.
-The third command ensures to install the BIDS schema code as an "editable" install,
-so that if you make changes to the schema files,
-these are automatically reflected in the sourcecode.
 
-Note that if you need to work on the some of the Python code
+Note that if you need to work on some of the Python code
 that is used to render the specification,
 you will probably have to also run: