doc: edit building-node text

Simplifying some BUILDING.md and related text since a lot of people will
be reading it soon for Code & Learn. I'd prefer to delete much of this
text, but that risks controversy. These simplifications should be (I
hope) uncontroversial.

PR-URL: #23335
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>

Author: Trott

BUILDING.md

@@ -1,10 +1,10 @@
 # Building Node.js
 
-Depending on what platform or features you require, the build process may
-differ slightly. After you've successfully built a binary, running the
-test suite to validate that the binary works as intended is a good next step.
+Depending on what platform or features you need, the build process may
+differ. After you've built a binary, running the
+test suite to confirm that the binary works as intended is a good next step.
 
-If you can reproduce a test failure consistently, search for it in the
+If you can reproduce a test failure, search for it in the
 [Node.js issue tracker](https://github.com/nodejs/node/issues) or
 file a new issue.
 

README.md

@@ -155,9 +155,8 @@ the file's signature.
 
 ## Building Node.js
 
-See [BUILDING.md](BUILDING.md) for instructions on how to build
-Node.js from source. The document also contains a list of
-officially supported platforms.
+See [BUILDING.md](BUILDING.md) for instructions on how to build Node.js from
+source and a list of supported platforms.
 
 ## Security