Fix a number of typos etc. plus add a short paragraph how svn_cache__t instances relate to the big singleton membuffer cache instance.
Fix a number of typos etc. plus add a short paragraph how svn_cache__t
instances relate to the big singleton membuffer cache instance.

* subversion/libsvn_subr/cache-membuffer.c: improve commentary

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion