Update various parts of the text.

There's no such thing as "early ReferenceError" anymore (for things like 0++); they're all just "early SyntaxError" now. tc39/ecma262#691

5.2.3
PICTURE clause character-string representation
Some PIC clause symbols can appear only once in a PIC clause character-string,
while other can appear more than once. For example:
➢ PIC clause to hold value 1123.45 is coded as follows, where the V represents
the decimal position.
PIC 9(4)V99
➢ PIC clause for a value such as $1,123.45 is coded as follows:
PIC $9,999V99

Please forgive the provocative and overly broad title. ;)

Opening the very first examples in IDEA, we immediately get suggestions. For instance:

And you see the grey wrigglies indicating that IDEA thinks we should use isNotEmpty().

If this is not a conscious decision,

I would like to ask if the lesson Plotting and programming with Python should be included in the list of lessons available presented in the README.

Thanks for contributing! If this contribution is for instructor training, please send an email to checkout@carpentries.org with a link to this contribution so we can record your prog

It would be nice to have some test that checks documents formatting. Incorrect formatting influences bad document rendering and causes difficulties in translation in Transifex as one sentence is split across several lines wich Transifex shows separately. English has a fixed sentence structure and it is very hard to get the meaning of the sentence by its small part.

With community PGI on Fedora 30 x86_64

$ make c++
pgc++ -o pic.exe pic.cpp -fast -Minfo=opt
"/usr/include/c++/9/bits/stl_function.h", line 437: error: identifier
          "__builtin_is_constant_evaluated" is undefined
  	if (__builtin_is_constant_evaluated())
  	    ^

1 error detected in the compilation of "pic.cpp".
make: *** [Makefile:14: pic.exe] Error 2

$ pgc++ -V