chore: two grammar changes in profile readme

[ggwicz]

Hello! I wanted to propose two small grammar changes that I hope will refine the nodejs GitHub organization's profile readme.

1. Remove Unnecessary Em Dash

The current readme has an em dash in the middle of its opening sentence:

Node.js® is a free, open-source, cross-platform JavaScript run-time environment—that lets developers write command line tools and server-side scripts outside of a browser.

Em dash usage is subjective, but I don't think it belongs here. Em dashes are generally best for moving sentences in a new direction, like a "more powerful" parenthetical.

In my view, the current sentence in the profile readme does not need a separator of any kind. It's not expressing two ideas. It's one singular, coherent explanation of Node.js, and I think it works better as a single clause:

Node.js® is a free, open-source, cross-platform JavaScript run-time environment that lets developers write command line tools and server-side scripts outside of a browser.

2. Fix Typo in Code of Conduct Section

The readme's section about the Code of Conduct currently has a typo (emphasis mine):

Help us making this Community safe.

There are several ways this could be fixed. I've proposed the following in this PR:

Making this Community safe.

This is a small change, and in my view maintains a good consistency across the main verb of each header:

👋 Contributing ...
🦺 Making ...
👾 Reporting ...

But there are other ways this could be fixed. Alternative ideas include:

Help us in making this Community safe.
Help us make this Community safe.