Minor wording change (#223)

nw31304 · web-flow · commit 60dd6f2e85a8 · 2021-12-07T21:36:21.000+02:00
diff --git a/core/index.rst b/core/index.rst
@@ -16,7 +16,7 @@
 PlatformIO Core (CLI)
 =====================
 
-|PIOCORE| (CLI tool) is a heart of whole PlatformIO ecosystem and consists of
+|PIOCORE| (CLI tool) is the heart of the entire PlatformIO ecosystem and consists of
 
 * Multi-platform Build System
 * Development platform and package managers
