When use pygment in Jekyll,you should use as follow:

{% highlight nginx %}
http{}
mail{}
tcp {
        upstream tcp_socket {
              server localhost:8751;
              check interval=3000 rise=2 fall=5 timeout=1000;
        } 
        server {
              listen 8750;
              proxy_pass tcp_socket;
        }
}
{% endhighlight %}

List of lexers/highlighters supported by pygments:

Format Short names for highlight tag
Debian Sourcelist sourceslist, sources.list
Delphi delphi, pas, pascal, objectpascal
JavaScript+Mako js+mako, javascript+mako
Elixir iex session iex
PostgreSQL console (psql) psql, postgresql-console, postgres-console
Brainfuck brainfuck, bf
Ceylon ceylon
JavaScript+Django/Jinja js+django, javascript+django, js+jinja, javascript+jinja
HTML+Evoque html+evoque
NumPy numpy
Modula-2 modula2, m2
LiveScript live-script, livescript
Nimrod nimrod, nim
Bash bash, sh, ksh
HTML+Django/Jinja html+django, html+jinja
CSS+PHP css+php
XML+Lasso xml+lasso
VimL vim
CSS+Genshi Text css+genshitext, css+genshi
Fancy fancy, fy
Coldfusion HTML cfm
cfstatement cfs
Scalate Server Page ssp
Smarty smarty
XML+Evoque xml+evoque
haXe hx, haXe
PowerShell powershell, posh, ps1
Tea tea
HTML+Cheetah html+cheetah, html+spitfire
Ruby irb session rbcon, irb
Mason mason
Django/Jinja django, jinja
JAGS jags
ApacheConf apacheconf, aconf, apache
DTD dtd
Dylan session dylan-console, dylan-repl
Lighttpd configuration file lighty, lighttpd
Java java
JavaScript+Genshi Text js+genshitext, js+genshi, javascript+genshitext, javascript+genshi
Scheme scheme, scm
Nemerle nemerle
RHTML rhtml, html+erb, html+ruby
Ragel in Java Host ragel-java
Darcs Patch dpatch
Puppet puppet
Octave octave
CoffeeScript coffee-script, coffeescript
Ragel in D Host ragel-d
Scilab scilab
Monkey monkey
HTML+Myghty html+myghty
Erlang erl session erl
CSS css
JavaScript+Smarty js+smarty, javascript+smarty
Io io
COBOLFree cobolfree
Asymptote asy, asymptote
vhdl vhdl
Python 3 python3, py3
CSS+Ruby css+erb, css+ruby
Fortran fortran
d-objdump d-objdump
MySQL mysql
REBOL rebol
C++ cpp, c++
ERB erb
CBM BASIC V2 cbmbas
Befunge befunge
Julia julia, jl
MoonScript moon, moonscript
Ruby rb, ruby, duby
XML+Smarty xml+smarty
Dylan dylan
Groovy groovy
MoinMoin/Trac Wiki markup trac-wiki, moin
autohotkey ahk
C c
HTML html
Felix felix, flx
CMake cmake
NSIS nsis, nsi, nsh
SourcePawn sp
Mako mako
VGL vgl
Velocity velocity
Koka koka
CUDA cuda, cu
Gnuplot gnuplot
IRC logs irc
Prolog prolog
Python python, py, sage
CSS+Django/Jinja css+django, css+jinja
verilog verilog, v
Smalltalk smalltalk, squeak
JavaScript+Myghty js+myghty, javascript+myghty
YAML yaml
ANTLR With ActionScript Target antlr-as, antlr-actionscript
XML+Mako xml+mako
XSLT xslt
UrbiScript urbiscript
Scaml scaml, SCAML
S splus, s, r
DylanLID dylan-lid, lid
MAQL maql
sqlite3con sqlite3
Boo boo
OCaml ocaml
eC ec
ActionScript as, actionscript
VB.net vb.net, vbnet
SquidConf squidconf, squid.conf, squid
XQuery xquery, xqy, xq, xql, xqm
D d
Fantom fan
Gettext Catalog pot, po
Logos logos
Julia console jlcon
Lasso lasso, lassoscript
SCSS scss
BBCode bbcode
Haml haml, HAML
FoxPro Clipper, XBase
Python 3.0 Traceback py3tb
MuPAD mupad
XML+Ruby xml+erb, xml+ruby
Dart dart
IDL idl
dg dg
Evoque evoque
Jade jade, JADE
c-objdump c-objdump
Kconfig kconfig, menuconfig, linux-config, kernel-config
Java Server Page jsp
reg registry
ABAP abap
XML+Velocity xml+velocity
JavaScript+Cheetah js+cheetah, javascript+cheetah, js+spitfire, javascript+spitfire
HTML+Mako html+mako
Ragel in Ruby Host ragel-ruby, ragel-rb
RobotFramework RobotFramework, robotframework
Protocol Buffer protobuf
CFEngine3 cfengine3, cf3
Ragel ragel
GLSL glsl
COBOL cobol
TypeScript ts
Ada ada, ada95ada2005
PostgreSQL SQL dialect postgresql, postgres
Xtend xtend
Logtalk logtalk
objdump objdump
CSS+Mako css+mako
ca65 ca65
Objective-C++ objective-c++, objectivec++, obj-c++, objc++
Gherkin Cucumber, cucumber, Gherkin, gherkin
HTML+PHP html+php
Makefile make, makefile, mf, bsdmake
PostScript postscript
Hxml haxeml, hxml
Kotlin kotlin
PL/pgSQL plpgsql
Vala vala, vapi
Haskell haskell, hs
Bro bro
Lua lua
POVRay pov
Sass sass, SASS
ANTLR With Java Target antlr-java
Tcl tcl
ANTLR With ObjectiveC Target antlr-objc
JavaScript+Ruby js+erb, javascript+erb, js+ruby, javascript+ruby
Racket racket, rkt
AspectJ aspectj
Base Makefile basemake
ANTLR With Python Target antlr-python
cpp-objdump cpp-objdump, c++-objdumb, cxx-objdump
Genshi Text genshitext
Ioke ioke, ik
PyPy Log pypylog, pypy
Croc croc
Objective-J objective-j, objectivej, obj-j, objj
GAS gas
Batchfile bat
Snobol snobol
Python console session pycon
XML xml
ANTLR antlr
Opa opa
XML+Cheetah xml+cheetah, xml+spitfire
Go go
Diff diff, udiff
MiniD minid
Cython cython, pyx
Ragel in C Host ragel-c
Erlang erlang
Debian Control file control
aspx-vb aspx-vb
BUGS bugs, winbugs, openbugs
Ragel in CPP Host ragel-cpp
aspx-cs aspx-cs
Matlab session matlabsession
Properties properties
Groff groff, nroff, man
Clojure clojure, clj
Modelica modelica
QML qml, Qt Meta Language, Qt modeling Language
JavaScript+Lasso js+lasso, javascript+lasso
ANTLR With Perl Target antlr-perl
Genshi genshi, kid, xml+genshi, xml+kid
BlitzMax blitzmax, bmax
Treetop treetop
Matlab matlab
Myghty myghty
HTML+Genshi html+genshi, html+kid
Duel duel, Duel Engine, Duel View, JBST, jbst, JsonML+BST
Perl perl, pl
FSharp fsharp
reStructuredText rst, rest, restructuredtext
NewLisp newlisp
Scala scala
CSS+Lasso css+lasso
XML+PHP xml+php
Stan stan
INI ini, cfg
MOOCode moocode
Shell Session shell-session
RPMSpec spec
Newspeak newspeak
Bash Session console
Coq coq
Raw token data raw
Tcsh tcsh, csh
HTML+Lasso html+lasso
C# csharp, c#
Gosu Template gst
RConsole rconsole, rout
MXML mxml
TeX tex, latex
CSS+Smarty css+smarty
Text only text
ANTLR With C# Target antlr-csharp, antlr-c#
OpenEdge ABL openedge, abl, progress
Cheetah cheetah, spitfire
Smali smali
CSS+Myghty css+myghty
Rd rd
LLVM llvm
Standard ML sml
Elixir elixir, ex, exs
Nginx configuration file nginx
GoodData-CL gooddata-cl
AppleScript applescript
HTML+Smarty html+smarty
Objective-C objective-c, objectivec, obj-c, objc
JavaScript js, javascript
Rust rust
Common Lisp common-lisp, cl
Embedded Ragel ragel-em
ActionScript 3 as3, actionscript3
systemverilog systemverilog, sv
Literate Haskell lhs, literate-haskell
Python Traceback pytb
PHP php, php3, php4, php5
ANTLR With CPP Target antlr-cpp
Gosu gosu
Hybris hybris, hy
JavaScript+PHP js+php, javascript+php
Factor factor
HTML+Velocity html+velocity
Mscgen mscgen, msc
Ooc ooc
SQL sql
HTTP http
ECL ecl
Redcode redcode
Ragel in Objective C Host ragel-objc
XML+Django/Jinja xml+django, xml+jinja
Awk awk, gawk, mawk, nawk
JSON json
NASM nasm
ANTLR With Ruby Target antlr-ruby, antlr-rb
XML+Myghty xml+myghty
AutoIt autoit, Autoit