Issue 12329: XHTML entity apos missing in htmlentitydefs

In module htmlentitydefs.py the following XHTML-1 entity is missing from 
dict name2codepoint:

    'apos':     0x0027, # apostrophe, U+0027 ISOnum

Above line should be added after line 72:
    'ang':      0x2220, # angle, U+2220 ISOamso