readme: nuke "using npm programmatically" section

The programmatic `npm` API is unsupported, and is not guaranteed not to break in non-major versions.

Removing this section so newcomers aren't encouraged to discover or use it.

PR-URL: #11130
Credit: @ljharb
Reviewed-By: @othiym23

README.md

@@ -138,52 +138,6 @@ must remove them yourself manually if you want them gone.  Note that
 this means that future npm installs will not remember the settings that
 you have chosen.
 
-## Using npm Programmatically
-
-Although npm can be used programmatically, its API is meant for use by the CLI
-*only*, and no guarantees are made regarding its fitness for any other purpose.
-If you want to use npm to reliably perform some task, the safest thing to do is
-to invoke the desired `npm` command with appropriate arguments.
-
-The semantic version of npm refers to the CLI itself, rather than the
-underlying API. _The internal API is not guaranteed to remain stable even when
-npm's version indicates no breaking changes have been made according to
-semver._
-
-If you _still_ would like to use npm programmatically, it's _possible_. The API
-isn't very well documented, but it _is_ rather simple.
-
-Eventually, npm will be just a thin CLI wrapper around the modules that it
-depends on, but for now, there are some things that only the CLI can do. You
-should try using one of npm's dependencies first, and only use the API if what
-you're trying to do is only supported by npm itself.
-
-```javascript
-var npm = require("npm")
-npm.load(myConfigObject, function (er) {
-  if (er) return handlError(er)
-  npm.commands.install(["some", "args"], function (er, data) {
-    if (er) return commandFailed(er)
-    // command succeeded, and data might have some info
-  })
-  npm.registry.log.on("log", function (message) { .... })
-})
-```
-
-The `load` function takes an object hash of the command-line configs.
-The various `npm.commands.<cmd>` functions take an **array** of
-positional argument **strings**.  The last argument to any
-`npm.commands.<cmd>` function is a callback.  Some commands take other
-optional arguments.  Read the source.
-
-You cannot set configs individually for any single npm function at this
-time.  Since `npm` is a singleton, any call to `npm.config.set` will
-change the value for *all* npm commands in that process.
-
-See `./bin/npm-cli.js` for an example of pulling config values off of the
-command line arguments using nopt.  You may also want to check out `npm
-help config` to learn about all the options you can set there.
-
 ## More Docs
 
 Check out the [docs](https://docs.npmjs.com/),