doc: document calling V from C

doc/docs.md

@@ -4268,6 +4268,23 @@ fn main() {
 }
 ```
 
+## Calling V from C
+
+Since V can compile to C, calling V code from C is very easy. 
+
+By default all V functions have the following naming scheme in C: `[module name]__[fn_name]`.
+
+For example, `fn foo() {}` in module `bar` will result in `foo__bar()`.
+
+To use a custom export name, use the `[export]` attribute:
+
+```
+[export: 'my_custom_c_name']
+fn foo() {
+}
+```
+
+
 ## Atomics
 
 V has no special support for atomics, yet, nevertheless it's possible to treat variables as atomics