feat(#343): POC: show defect context if @line attributes are empty

[h1alexbel]

In this PR I've implemented Proof Of Concept of printing defect's context, if inspected XMIR doesn't have @line attributes inside.

see #343
History:

• feat(Add Location of a Problem if @line Attribute is Absent #343): print first N chars
• feat(Add Location of a Problem if @line Attribute is Absent #343): poc

[h1alexbel]

@volodya-lombrozo take a look, please

[volodya-lombrozo]

@h1alexbel Thank you for the contribution! Just one small comment.
Additionally, maybe we can add a puzzle that would suggest to fix the issue with large context values? What do you think?

[volodya-lombrozo]

@h1alexbel [NIT] Can we put exact numbers here 0.1.0 or 0.0.40 ?

[h1alexbel]

@h1alexbel Thank you for the contribution! Just one small comment. Additionally, maybe we can add a puzzle that would suggest to fix the issue with large context values? What do you think?

@volodya-lombrozo for lage-context values, we already show only first 300 chars from the context string. In defect-context.xsl we do:

<xsl:value-of select="substring(serialize($context, map{'method':'xml'}), 1, 300)"/>

[volodya-lombrozo]

@h1alexbel Thank you for the contribution! Just one small comment. Additionally, maybe we can add a puzzle that would suggest to fix the issue with large context values? What do you think?

@volodya-lombrozo for lage-context values, we already show only first 300 chars from the context string. In defect-context.xsl we do:

<xsl:value-of select="substring(serialize($context, map{'method':'xml'}), 1, 300)"/>

@h1alexbel Could you add the test for this case please?

[h1alexbel]

@volodya-lombrozo updated. Take a look, please

[volodya-lombrozo]

@h1alexbel Looks good to me, thank you!

[h1alexbel]

@yegor256 take a look, please, what do you think about such feature?

[h1alexbel]

@yegor256 reminder