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_casecmp.md

@@ -0,0 +1,10 @@
+---
+title: "mg_casecmp()"
+decl_name: "mg_casecmp"
+symbol_kind: "func"
+signature: |
+  int mg_casecmp(const char *s1, const char *s2);
+---
+
+Cross-platform version of `strcasecmp()`. 
+