Error messages hard to read

[akaroml]

When editing pom.xml file with an error, the error message showed by XML extension is very hard to read.

It's too long
It has too much information and unnecessary details
It does not provide clear action items

Please consider improve the message by:

1. Remove all the namespaces before the actual element names: e.g. {"http://maven.apache.org/POM/4.0.0":name2} -> name2
2. Incorporate proper formatting/coloring to improve readability
3. Check similarity of the node name and rank the most possible one on top

Sample:

[XML] Invalid content was found starting with element 'name2'.
Possible values:
-> name
description
packaging
url
...

[fbricon]

See upstream issue: eclipse-lemminx/lemminx#181

[fbricon]

So here's how it looks after overriding the error messages in eclipse-lemminx/lemminx#297:
Before:

After

I'm a bit concerned by the way vscode shows the error message in the problems view.

[fbricon]

I've opened microsoft/vscode#69473 about the diagnostic rendering

[fbricon]

Copying the upstream comment here about the changes:

Before:

After:

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Before:

After:

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Before:

After: (Uses single quotes now)

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Before:

After:

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Before:

After:

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Before:

After: