Fix vectorised replacement failures

[hadley]

• https://github.com/hughjonesd/huxtable
• https://github.com/stefano-meschiari/latex2exp
• https://github.com/eco-hydro/phenofit
• https://github.com/stevecondylios/priceR
• https://github.com/byzheng/rtiddlywiki
• https://github.com/mdlincoln/salty

[hadley]

This might be a fun challenge if you're very familiar with the package development process — you need install the dev version of string, fork each package, use pak::pak() to load all dependencies, then run tests/R CMD check, and fixes the revealed bugs in str_replace_all(). Previously the functions were passed a single function and now they're passed a character vector, so you'll need to figure out how to vectorise the existing code.