Some typos fixed in the extern_c documentation

Author: alrubio

mkdocs/docs/circom-language/templates-and-components.md

@@ -201,7 +201,7 @@ However, the way in which their computation is encoded is different from the one
 
 ### Extern C code in custom templates
 
-As a new feature, one can add the key word `extern_c` to custom templates as in
+As a new feature, one can add the keyword `extern_c` to custom templates as in
 ```
 template custom extern_c A() {
     signal input in;
@@ -211,10 +211,10 @@ template custom extern_c A() {
 }
 ```
 
-This feature has only impact when the compilation is used with the flag `--c` to generting C code as backend. Othewise, it is ignored.
+This feature has only an impact when the compilation is used with the flag `--c` to generate C code as backend. Otherwise, it is ignored.
 
 When `extern_c` is used and the circom program is compiled with `--c`, the compiler outputs the following information for each `extern_c`:
 ```
-*** The method void IsEqual(FrElement* out ,uint* size_out ,FrElement* in ,uint* size_in ); generated by the custom gate IsZero needs to be implemented ***
+*** The method void A(FrElement* out ,uint* size_out ,FrElement* in ,uint* size_in ); generated by the custom gate A needs to be implemented ***
 ```
 A cpp file (or several) including all the needed functions must be included in the generated `name_cpp` folder. Then, running `make` an executable uising these external functions will be generated.