Merge #13312: docs: Add a note about the source code filename naming convention

e56771365b Do not use uppercase characters in source code filenames (practicalswift)
419a1983ca docs: Add a note about the source code filename naming convention (practicalswift)

Pull request description:

  Add a note about the source code filename naming convention.

Tree-SHA512: 8d329bd9e19bcd26e74b0862fb0bc2369b46095dbd3e69d34859908632763abd7c3d00ccc44ee059772ad4bae4460c2bcc1c0e22fd9d8876d57e5fcd346cea4b

src/Makefile.bench.include

@@ -17,7 +17,7 @@ bench_bench_bitcoin_SOURCES = \
   bench/bench.h \
   bench/checkblock.cpp \
   bench/checkqueue.cpp \
-  bench/Examples.cpp \
+  bench/examples.cpp \
   bench/rollingbloom.cpp \
   bench/crypto_hash.cpp \
   bench/ccoins_caching.cpp \