fix #1470: the footnote backreference character is not a single chara…

…cter when katex is used for math, so instead of matching \X, we match a series of characters that are not <

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: bookdown
 Type: Package
 Title: Authoring Books and Technical Documents with R Markdown
-Version: 0.39.1
+Version: 0.39.2
 Authors@R: c(
     person("Yihui", "Xie", role = c("aut", "cre"), email = "[email protected]", comment = c(ORCID = "0000-0003-0645-5666")),
     person("Christophe", "Dervieux", , "[email protected]", role = c("ctb"),

NEWS.md

@@ -1,5 +1,6 @@
 # CHANGES IN bookdown VERSION 0.40
 
+- Footnotes are not rendered correctly when `katex` is used to render LaTeX math expressions (thanks, @pbreheny, #1470).
 
 # CHANGES IN bookdown VERSION 0.39
 

R/html.R

@@ -1030,7 +1030,7 @@ parse_footnotes = function(x) {
   j = which(x == '</div>')
   j = min(j[j > i])
   n = length(x)
-  r = '<li id="fn([0-9]+)"><p>(?s).+?<a href="#fnref\\1"[^>]*?>\\X</a></p></li>'
+  r = '<li id="fn([0-9]+)"><p>(?s).+?<a href="#fnref\\1"[^>]*?>[^<]+</a></p></li>'
   s = paste(x[i:n], collapse = '\n')
   items = unlist(regmatches(s, gregexpr(r, s, perl = TRUE)))
   list(items = setNames(items, gsub(r, 'fn\\1', items, perl = TRUE)), range = i:j)