Adding build instructions to Bitcoin Core, fixes #18658

Author: saahilshangle

README.md

@@ -25,7 +25,7 @@ information or see https://opensource.org/licenses/MIT.
 Development Process
 -------------------
 
-The `master` branch is regularly built and tested, but is not guaranteed to be
+The `master` branch is regularly built (see doc/build-*.md for instructions) and tested, but is not guaranteed to be
 completely stable. [Tags](https://github.com/bitcoin/bitcoin/tags) are created
 regularly to indicate new official, stable release versions of Bitcoin Core.