fix(snippetz): keep multiline strings and odd names valid in clj-http examples - #10507

Problem

Two things make the clj-http code example wrong or invalid Clojure:

• A body or JSON value that has a line break is written with a real new line inside the string. The example then adds indentation after each new line to line up the map, so that indentation becomes part of the string. The copied request sends a different body (extra spaces on every line).
• Header, query and form names are always written as keywords. A name like X Custom or filter[name] gives :X Custom, which is not valid Clojure.

Solution

Write line breaks as \n and \r escapes, so the layout padding can never end up inside a string. Names that are not valid keywords are written as string keys, which clj-http accepts for headers, query params and form params. Normal names still render as :name.

One existing test expected :special chars!@#, which is not valid Clojure, so I updated it to "special chars!@#". I added tests for a multiline text body, a multiline JSON value and header and query names with spaces and brackets. They fail without the fix.

Checklist

• I explained why the change is needed.
• I added a changeset.
• I added tests.
• I updated the documentation. (not needed, no docs describe this)