refine style guide

CONTRIBUTING.md

@@ -8,7 +8,7 @@ If you are eager to contribute to a NetFoundry-managed open source project pleas
 ## Project Styles
 
 This project uses several programming languages. Each language has its own style guide specifying any language-specific
-conventions and idioms.
+conventions and idioms. The log formatting examples for Go are applicable to all languages.
 
 ### Markdown
 
@@ -21,13 +21,33 @@ conventions and idioms.
 
 + This project uses [Go](https://golang.org/) language conventions.
 + Organize imports as a single block in alphabetical order without empty lines.
-+ Begin log messages with a lowercase letter and do not end with punctuation.
++ Begin log messages with a lowercase letter and do not end with punctuation. This log formatting guidance applies to all languages, not only Go.
+
+    Format log messages that report errors.
+
+    ```go
+    logrus.Errorf("tried a thing and failed: %v", err)
+    ```
+
+    Format in-line information in informational log messages.
+
+    ```go
+    logrus.Infof("the expected value '%v' arrived as '%v'", expected, actual)
+    ```
+
+    Format in-line information in error log messages.
+
+    ```go
+    logrus.Errorf("the expected value '%v did not compute: %v", value, err)
+    ```
+
 + Format log messages with format strings and arguments like 'tried a thing and failed: %s'.
 
 ### Python
 
 + This project uses [Python](https://www.python.org/) language conventions PEP-8.
 + Use [flake8](https://flake8.pycqa.org/en/latest/) with [the configuration file](.flake8) committed to this repository to find formatting problems.
++ Use Go log formatting guidance for Python too.
 
 ### Docusaurus