Merge pull request bitcoin#1450 from yahiheb/patch-1

[Trivial] Fix text format (BIP 39)

Author: kallewoof

bip-0039.mediawiki

@@ -39,7 +39,7 @@ security is improved but the sentence length increases. We refer to the
 initial entropy length as ENT. The allowed size of ENT is 128-256 bits.
 
 First, an initial entropy of ENT bits is generated. A checksum is generated by
-taking the first <pre>ENT / 32</pre> bits of its SHA256 hash. This checksum is
+taking the first <code>ENT / 32</code> bits of its SHA256 hash. This checksum is
 appended to the end of the initial entropy. Next, these concatenated bits
 are split into groups of 11 bits, each encoding a number from 0-2047, serving
 as an index into a wordlist. Finally, we convert these numbers into words and