No stripping occurs if the code span contains only spaces

[lostenderman]

See https://spec.commonmark.org/0.30/#example-334

[Witiko]

This issue is a duplicate of issue #107.

[lostenderman]

Not closing after pull #111, example 334 fails.

Spaces are not preserved in the output.

[Witiko]

The corresponding unit test is testfiles/CommonMark_0.30/code_spans/007.test:

%   ---RESULT--- "example": 334,
%   
%   <p><code> </code>
%   <code>  </code></p>
%   
%   ---\RESULT---

<<<
` `
`  `
>>>
documentBegin
codeSpan:  
codeSpan:   
documentEnd

Here is the result of running git checkout commonmark; cd tests; ./test.sh "testfiles/CommonMark_0.30/code_spans/007.test":

Testfile testfiles/CommonMark_0.30/code_spans/007.test
  Format templates/plain/
    Template templates/plain/input.tex.m4
      Command luatex                                   --interaction=nonstopmode  test.tex
*** test-expected.log	2023-01-04 01:07:19.506601678 +0100
--- test-actual.log	2023-01-04 01:07:25.656556667 +0100
***************
*** 1,4 ****
  documentBegin
! codeSpan:  
! codeSpan:   
  documentEnd
--- 1,4 ----
  documentBegin
! codeSpan: 
! codeSpan: 
  documentEnd

The issue seems related to the PEG patterns for parsing code spans (1, 2), which use the rules for Gruber's Markdown rather than CommonMark.