feat: wrap line mode #21

[lvolland]

{ wrap: true } on highlightText / highlightElement / highlightAll.

the reason this was never a one-liner: white-space: pre-wrap on the current markup wraps
the text fine, but the gutter is a separate column of one div per source line, so as soon as
a line wraps the numbers slide out of step with the code.

the middle panel is what people reach for today — by line 8 the gutter is lying:

so in wrap mode each line becomes its own grid row — number cell, code cell — and a token
that spans a newline is split at the newline so every cell stays balanced.

highlightText(code, 'js', true, { wrap: true })

cost

dist/index.js         +94 bytes gzipped
dist/themes/*.css     +58 bytes gzipped

nothing else changes: the css goes in default.css, which every other theme already
@imports, and the number cells keep the shj-numbers class so the six themes that
recolour the gutter keep working.

verified

108/108   default output byte-identical to 1.2.19
          36 fixtures × { }, { hideLineNumbers }, multiline=false
36/36     wrap output: text reconstructs exactly, spans balanced inside every
          cell, one cell per source line
8/8       edge cases: empty, single line, crlf, trailing newline, only newlines,
          unterminated string, unterminated block comment, emoji + accents

notes

• { wrap: true, hideLineNumbers: true } needs no grid at all, so it keeps the current
  markup and only flips white-space — no per-line splitting, no extra bytes in the output
• counter-reset: line moves from .shj-numbers up to its parent. same result on the
  existing markup, and it lets the grid reuse the counter
• wrap mode inherits the trailing-newline behaviour from the default path — the phantom last
  number. fix: a trailing newline adds a phantom line number #80 fixes that in the default path; happy to align both once you've picked a side
• i did not touch dist/