Error message when a word starts with a number followed by a letter.

[jmbragg]

When trying to match 2Cl-(aq) , I have a part that I wanted to read 2Cl(sup)-(/sup)_aq but when entering it gave the error "Non recognized sub content in code fragment "match_all ( mat"." I ended up with 2_Cl(sup)-(/sup)_aq instead and that works.

Please note that in this version ( and ) have been added as characters to treat as spaces.

I've changed all the < in the text to ( so Github will stop changing my text...