Fix highlighting issue when printing JSON that isn't indented

[darrenburns]

Type of changes

• Bug fix
• New feature
• Documentation / docstrings
• Tests
• Other

Checklist

• I've run the latest black with default args on new code.
• I've updated CHANGELOG.md and CONTRIBUTORS.md where appropriate.
• I've added tests for new code.
• I accept that @willmcgugan may be pedantic in the code review.

Description

Previously the JSONHighlighter would do two passes with Text.highlight - the second pass would highlight JSON keys.

I've got rid of the second regex for the 2nd Text.highlight pass, and replaced it with a regex which captures the spans of strings, followed by some manual processing to determine whether they're keys or not. If the string is a key, we append the json.key Span.

Previously:

Closes #2027

[codecov-commenter]

Codecov Report

Merging #2038 (93e584c) into master (75f4637) will decrease coverage by 0.02%.
The diff coverage is 96.29%.

❗ Current head 93e584c differs from pull request most recent head 9e3ae26. Consider uploading reports for the commit 9e3ae26 to get more accurate results

@@            Coverage Diff             @@
##           master    #2038      +/-   ##
==========================================
- Coverage   99.81%   99.78%   -0.03%     
==========================================
  Files          71       71              
  Lines        7058     7107      +49     
==========================================
+ Hits         7045     7092      +47     
- Misses         13       15       +2     

Flag	Coverage Δ
unittests	99.78% <96.29%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
rich/console.py	100.00% <ø> (ø)
rich/pretty.py	99.21% <93.93%> (-0.50%)	⬇️
rich/__init__.py	100.00% <100.00%> (ø)
rich/_inspect.py	100.00% <100.00%> (ø)
rich/highlighter.py	100.00% <100.00%> (ø)

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[willmcgugan]

Just a couple of requests, as discussed...

[willmcgugan]

LGTM