Fix of screen section clauses

[engboris]

Fix for bug #947 on Sourceforge

The VALUE ALL '-' clause in SCREEN SECTION did not work (error message error: syntax error, unexpected ALL) although it should have.

Screen sections used clauses with basic_literal which does not allow the ALL keyword. I remplaced it by the literal construction (already defined) which extends basic_literal with the ALL keyword.

I added a test in testsuite/syn_screen.at (at the end) based on the code provided in the bug report.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (2ff35a3) 65.74% compared to head (37eae71) 65.78%. Report is 4 commits behind head on gcos4gnucobol-3.x.

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## gcos4gnucobol-3.x #135 +/- ## ===================================================== + Coverage 65.74% 65.78% +0.03% ===================================================== Files 32 32 Lines 59380 59416 +36 Branches 15683 15694 +11 ===================================================== + Hits 39040 39086 +46 + Misses 14326 14312 -14 - Partials 6014 6018 +4 ```

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[engboris]

I believe so. The test displays a sequence of "-" symbols and that's what I get.

[engboris]

I believe it should have a "Ready for SVN" label?

[ddeclerck]

Merged in SVN at revision 5226. (@GitMensch Can you reattribute this to user "engboris" ?)

[GitMensch]

Thanks for the check-in; metadata was updated in svn and bug ticket closed