doc: make info why we force protofbuf compile more specific

Gemfile

@@ -81,7 +81,10 @@ gem 'gitable', require: "gitable/uri"
 gem 'mini_racer', '~> 0.16.0'    # minimal Google V8 JS engine for execjs
 gem 'libv8-node', '~> 18.19.0.0' # V8 JS engine
 
-# alpine specific
-# this fixes an issue with the libv8-node gem
-# otherwise it will segfault when using the precompiled binary from the gem
+# Alpine specific
+#
+# There is an issue with rails -> sass-embedded -> libv8-node -> protobuf
+#
+# We have to force bundler to compile protobuf on the current platform
+# and do not download precompile binary-gems, otherwise the usage of relying gems will segfault
 gem 'google-protobuf', force_ruby_platform: true