[trac3576] Restore line accidently removed from DHCPv4 guide, fix typo in comment

doc/guide/dhcp4-srv.xml

@@ -1088,6 +1088,7 @@ It is merely echoed by the server
 <row><entry>client-system</entry><entry>93</entry><entry>uint16</entry><entry>true</entry><entry>false</entry></row>
 <row><entry>client-ndi</entry><entry>94</entry><entry>record</entry><entry>false</entry><entry>false</entry></row>
 <row><entry>uuid-guid</entry><entry>97</entry><entry>record</entry><entry>false</entry><entry>false</entry></row>
+<row><entry>subnet-selection</entry><entry>118</entry><entry>ipv4-address</entry><entry>false</entry><entry>false</entry></row>
 <row><entry>domain-search</entry><entry>119</entry><entry>binary</entry><entry>false</entry><entry>false</entry></row>
 <row><entry>vivco-suboptions</entry><entry>124</entry><entry>binary</entry><entry>false</entry><entry>false</entry></row>
 <row><entry>vivso-suboptions</entry><entry>125</entry><entry>binary</entry><entry>false</entry><entry>false</entry></row>

src/lib/dhcp/std_option_defs.h

@@ -74,7 +74,7 @@ RECORD_DECL(VIVCO_RECORDS, OPT_UINT32_TYPE, OPT_BINARY_TYPE);
 
 // RFC4578 (PXE) record fields
 //
-// Three 1 byte fileds to describe a network interface: type, major and minor
+// Three 1 byte fields to describe a network interface: type, major and minor
 RECORD_DECL(CLIENT_NDI_RECORDS, OPT_UINT8_TYPE, OPT_UINT8_TYPE, OPT_UINT8_TYPE);
 // A client identifer: a 1 byte type field followed by opaque data depending on the type
 RECORD_DECL(UUID_GUID_RECORDS, OPT_UINT8_TYPE, OPT_BINARY_TYPE);