Update documentation to syntax highlight code

googletest/docs/PumpManual.md

@@ -71,7 +71,7 @@ $if i == 0 [[
 
 will be translated by the Pump compiler to:
 
-```
+``` cpp
 // Foo0 does blah for 0-ary predicates.
 template <size_t N>
 class Foo0 {
@@ -107,7 +107,7 @@ $$ The text between i and [[ is the separator between iterations.
 
 will generate one of the following lines (without the comments), depending on the value of `n`:
 
-```
+``` cpp
 Func();              // If n is 0.
 Func(a1);            // If n is 1.
 Func(a1 + a2);       // If n is 2.
@@ -140,7 +140,7 @@ up in your output.
 
 ## Grammar ##
 
-```
+``` ebnf
 code ::= atomic_code*
 atomic_code ::= $var id = exp
     | $var id = [[ code ]]