rewrite_block clamps a requested paragraph width between the text's
size in user space (size * k) and the largest page PDF allows
(14 400 pt). f64::clamp panics when its minimum is the larger, so text
set above 14 400 pt crashed the app as soon as its paragraph was given
a width. The size comes from the file (`20000 Tf`, or `1 Tf` scaled up
by `Tm`) or from the request (the automation tools pass `size`
through).
The lower bound is now capped at 14 400 pt too, so such a paragraph
gets the widest width allowed. `f64::min` also turns a NaN size into
the cap.
Test: a 20000 pt Tf, a 1 pt Tf scaled 20000x by Tm, and a requested
size of 20000 pt each take a width of 200 without panicking (all three
panicked before).
Reported-by: BS.ehlas.cz
Co-authored-by: Brandon Thomas <echelon@gmail.com>
Reduce File Size removes named destinations that nothing refers to. It
collected the referenced names by reading /Dest and a GoTo's /D
directly, so when a link's /Dest was an indirect reference to the name
string (valid PDF) rather than the string itself, the name was not
counted. The destination it used was then treated as unreferenced and
deleted, silently breaking the link.
referenced_names now resolves /Dest and /D before reading the name, so
an indirectly referenced destination is kept.
Test: a link whose /Dest is a reference to the name string keeps its
destination through optimize(); an unused destination is still removed.
Reported-by: BS.ehlas.cz
