Add documentation index for doc/ as README.md, and small docs fixes (#16253)

doc/README.md

@@ -0,0 +1,60 @@
+# Documentation
+
+This directory contains mostly reference documentation for the Luanti engine.
+For a less prescriptive and more guiding documentation, also look at:
+https://docs.luanti.org
+
+Note that the inner workings of the engine are not well documented. It's most
+often better to read the code.
+
+Markdown files are written in a way that they can also be read in plain text.
+When modifying, please keep it that way!
+
+Here is a list with descriptions of relevant files:
+
+## Server Modding
+
+- [lua_api.md](lua_api.md): Server Modding API reference. (Not only the Lua part,
+    but also file structure and everything else.)
+    If you want to make a mod or game, look here!
+    A rendered version is also available at <https://api.luanti.org/>.
+- [builtin_entities.md](builtin_entities.md): Doc for entities predefined by the
+    engine (in builtin), i.e. dropped items and falling nodes.
+
+## Client-Side Content
+
+- [texture_packs.md](texture_packs.md): Layout and description of Luanti's
+    texture packs structure and configuration.
+- [client_lua_api.md](client_lua_api.md): Client-Provided Client-Side Modding
+    (CPCSM) API reference.
+
+## Mainmenu scripting
+
+- [menu_lua_api.md](menu_lua_api.md): API reference for the mainmenu scripting
+    environment.
+- [fst_api.txt](fst_api.txt): Formspec Toolkit API, included in builtin for the
+    main menu.
+
+## Formats and Protocols
+
+- [world_format.md](world_format.md): Structure of Luanti world directories and
+    format of the files therein.
+    Note: If you want to write your own deserializer, it will be easier to read
+    the `serialize()` and `deSerialize()` functions of the various structures in
+    C++, e.g. `MapBlock::deSerialize()`.
+- [protocol.txt](protocol.txt): *Rough* outline of Luanti's network protocol.
+
+## Misc.
+
+- [compiling/](compiling/): Compilation instructions, and options.
+- [ides/](ides/): Instructions for configuring certain IDEs for engine development.
+- [developing/](developing/): Information about Luanti development.
+    Note: [developing/profiling.md](developing/profiling.md) can be useful for
+    modders and server owners!
+- [android.md](android.md): Android quirks.
+- [direction.md](direction.md): Information related to the future direction of
+    Luanti. Commonly referred to as the roadmap document.
+- [breakages.md](breakages.md): List of planned breakages for the next major
+    release, i.e. 6.0.0.
+- [docker_server.md](docker_server.md): Information about our Docker server
+    images in the ghcr.

doc/developing/README.md

@@ -2,7 +2,7 @@
 
 ## Luanti Documentation
 
-Some important development docs are found in the Luanti Documentation: https://docs.luanti.org/
+Some important development docs are found on the docs site: https://docs.luanti.org/
 
 Notable pages:
 
@@ -11,13 +11,14 @@ Notable pages:
 - [Changelog](https://docs.luanti.org/about/changelog/)
 - [Organisation](https://docs.luanti.org/for-engine-devs/organization/)
 - [Code style guidelines](https://docs.luanti.org/for-engine-devs/code-style-guidelines/)
+  and [Lua code style guidelines](https://docs.luanti.org/for-engine-devs/lua-code-style-guidelines/)
 
 ## In this folder
 
-- [Developing minetestserver with Docker](docker.md)
-- [Android tips & tricks](android.md)
-- [OS/library compatibility policy](os-compatibility.md)
-- [Miscellaneous](misc.md)
+- [docker.md](docker.md): Developing minetestserver with Docker
+- [android.md](android.md): Android tips & tricks
+- [os-compatibility.md](os-compatibility.md): OS/library compatibility policy
+- [profiling.md](profiling.md): Profiling instructions
 
 ## IRC
 

doc/developing/profiling.md

@@ -1,4 +1,4 @@
-# Miscellaneous
+# Profiling
 
 ## Profiling Luanti on Linux with perf
 

doc/fst_api.txt

@@ -3,8 +3,10 @@ Formspec toolkit api 0.0.3
 
 Formspec toolkit is a set of functions to create basic ui elements.
 
+You can find the files in builtin/fstk/.
 
-File: fst/ui.lua
+
+File: fstk/ui.lua
 ----------------
 
 ui.lua adds base ui interface to add additional components to.
@@ -25,7 +27,7 @@ ui.find_by_name(name) --> returns component or nil
 ^ find a component within ui
 ^ name: name of component to look for
 
-File: fst/tabview.lua
+File: fstk/tabview.lua
 ---------------------
 
 tabview_create(name, size, tabheaderpos) --> returns tabview component
@@ -92,7 +94,7 @@ methods:
       * icon: path to icon
       * on_click(tabview): callback function
 
-File: fst/dialog.lua
+File: fstk/dialog.lua
 ---------------------
 Only one dialog can be shown at a time. If a dialog is closed it's parent is
 gonna be activated and shown again.
@@ -129,7 +131,7 @@ members:
 - parent
   ^ parent component to return to on exit
 
-File: fst/buttonbar.lua
+File: fstk/buttonbar.lua
 -----------------------
 
 buttonbar_create(name, pos, size, bgcolor, cbf_buttonhandler)

doc/protocol.txt

@@ -3,7 +3,8 @@ Updated 2011-06-18
 
 A custom protocol over UDP.
 Integers are big endian.
-Refer to connection.{h,cpp} for further reference.
+Refer to network/mtp/internal.h, network/networkprotocol.{h,cpp}, and
+server/clientiface.h for further reference.
 
 Initialization:
 - A dummy reliable packet with peer_id=PEER_ID_INEXISTENT=0 is sent to the server: