Clean up and document project files (#4560)

docs/mkdocs/docs/examples/json_pointer.output

@@ -0,0 +1,3 @@
+[json.exception.parse_error.107] parse error at byte 1: JSON pointer must be empty or begin with '/' - was: 'foo'
+[json.exception.parse_error.108] parse error: escape character '~' must be followed with '0' or '1'
+[json.exception.parse_error.108] parse error: escape character '~' must be followed with '0' or '1'