Rollup merge of #74334 - jyn514:config-toml-docs, r=spastorino

bootstrap: Improve wording on docs for `verbose-tests`

From rust-lang/rustc-dev-guide#795 (comment)

r? @spastorino

Author: Manishearth

config.toml.example

@@ -391,8 +391,7 @@
 # desired in distributions, for example.
 #rpath = true
 
-# Emits extraneous output from tests to ensure that failures of the test
-# harness are debuggable just from logfiles.
+# Emits extra output from tests so test failures are debuggable just from logfiles.
 #verbose-tests = false
 
 # Flag indicating whether tests are compiled with optimizations (the -O flag).