Docs are generated for Mongoose

Comments in headers are changed a bit: removed adoc-specific stuff,
markdown is used instead

PUBLISHED_FROM=9242cce85cc52a47a197d377e7e23804721a6bb5

docs/c-api/util.h/mg_start_thread.md

@@ -0,0 +1,13 @@
+---
+title: "mg_start_thread()"
+decl_name: "mg_start_thread"
+symbol_kind: "func"
+signature: |
+  void *mg_start_thread(void *(*thread_func);
+---
+
+Start a new detached thread.
+Arguments and semantic is the same as pthead's `pthread_create()`.
+`thread_func` is a thread function, `thread_func_param` is a parameter
+that is passed to the thread function. 
+