Improve Linux developer documentation

* List CMake options in table
* Improve headline hierarchy
* Add .clangd config file so compile_commands.json gets found out-of-the-box

.clangd

@@ -0,0 +1,2 @@
+CompileFlags:
+	CompilationDatabase: ../vcmi-build

docs/developers/Building_Linux.md

@@ -1,13 +1,13 @@
-# Compiling VCMI
+# Building VCMI for Linux
 
 - Current baseline requirement for building is Ubuntu 20.04
 - Supported C++ compilers for UNIX-like systems are GCC 9+ and Clang 13+
 
 Older distributions and compilers might work, but they aren't tested by Github CI (Actions)
 
-# Installing dependencies
+# Prerequisites
 
-## Prerequisites
+## Installing dependencies
 
 To compile, the following packages (and their development counterparts) are needed to build:
 
@@ -21,7 +21,7 @@ To compile, the following packages (and their development counterparts) are need
     - if you want to build scripting modules: LuaJIT
     - to speed up recompilation: Ccache
 
-## On Debian-based systems (e.g. Ubuntu)
+### On Debian-based systems (e.g. Ubuntu)
 
 For Ubuntu and Debian you need to install this list of packages:
 
@@ -31,17 +31,17 @@ Alternatively if you have VCMI installed from repository or PPA you can use:
 
 `sudo apt-get build-dep vcmi`
 
-## On RPM-based distributions (e.g. Fedora)
+### On RPM-based distributions (e.g. Fedora)
 
 `sudo yum install cmake gcc-c++ SDL2-devel SDL2_image-devel SDL2_ttf-devel SDL2_mixer-devel boost boost-devel boost-filesystem boost-system boost-thread boost-program-options boost-locale boost-iostreams zlib-devel ffmpeg-devel ffmpeg-libs qt5-qtbase-devel tbb-devel luajit-devel liblzma-devel libsqlite3-devel fuzzylite-devel ccache`
 
 NOTE: `fuzzylite-devel` package is no longer available in recent version of Fedora, for example Fedora 38. It's not a blocker because VCMI bundles fuzzylite lib in its source code.
 
-## On Arch-based distributions
+### On Arch-based distributions
 
 On Arch-based distributions, there is a development package available for VCMI on the AUR.
 
-It can be found at: <https://aur.archlinux.org/packages/vcmi-git/>
+It can be found at https://aur.archlinux.org/packages/vcmi-git/
 
 Information about building packages from the Arch User Repository (AUR) can be found at the Arch wiki.
 
@@ -49,13 +49,13 @@ Information about building packages from the Arch User Repository (AUR) can be f
 
 We recommend the following directory structure:
 
-    .
-    ├── vcmi -> contains sources and is under git control
-    └── build -> contains build output, makefiles, object files,...
-
-Out-of-source builds keep the local repository clean so one doesn't have to manually exclude files generated during the build from commits.
+```
+.
+├── vcmi -> contains sources and is under git control
+└── vcmi-build -> contains build output, makefiles, object files,...
+```
 
-You can get latest sources with:
+You can get the latest source code with:
 
 `git clone -b develop --recursive https://github.com/vcmi/vcmi.git`
 
@@ -64,28 +64,34 @@ You can get latest sources with:
 ## Configuring Makefiles
 
 ```sh
-mkdir build && cd build
+mkdir vcmi-build
+cd vcmi-build
 cmake -S ../vcmi
 ```
 
-# Additional options that you may want to use:
+> [!NOTE]
+> The `../vcmi` is not a typo, it will place Makefiles into the build dir as the build dir is your working dir when calling CMake.
 
-## To enable debugging:
-`cmake -S ../vcmi -D CMAKE_BUILD_TYPE=Debug`
+### Additional options that you may want to use:
 
-**Notice**: The ../vcmi/ is not a typo, it will place makefile scripts into the build dir as the build dir is your working dir when calling CMake.
+| Option | Effect |
+|--------|--------|
+| -D CMAKE_BUILD_TYPE=Debug | Debug info and no optimizations |
+| -D ENABLE_CCACHE:BOOL=ON | Speeds up recompilation |
+| -D CMAKE_EXPORT_COMPILE_COMMANDS=ON | Creates `compile_commands.json` for `clangd` language server |
+| -G Ninja | Use Ninja build system instead of make, which speeds up the build and doesn't require a `-j` flag |
 
-## To use ccache:
-`cmake -S ../vcmi -D ENABLE_CCACHE:BOOL=ON`
+## Building
 
-## Trigger build
+```
+cmake --build . -j8
+```
 
-`cmake --build . -- -j2`
-(-j2 = compile with 2 threads, you can specify any value)
+(-j8 = compile with 8 threads, you can specify any value. )
 
-That will generate vcmiclient, vcmiserver, vcmilauncher as well as .so libraries in the **build/bin/** directory.
+This will generate `vcmiclient`, `vcmiserver`, `vcmilauncher` as well as .so libraries in the `build/bin/` directory.
 
-# Package building
+# Packaging
 
 ## RPM package
 
@@ -97,7 +103,8 @@ The first step is to prepare a RPM build environment. On Fedora systems you can
 sudo dnf install https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm
 ```
 
-NOTE: the stock ffmpeg from Fedora repo is no good as it has stripped lots of codecs
+> [!NOTE]
+> The stock ffmpeg from Fedora repo is no good as it lacks a lots of codecs
 
 1. Perform a git clone from a tagged branch for the right Fedora version from https://github.com/rpmfusion/vcmi; for example for Fedora 38: <pre>git clone -b f38 --single-branch https://github.com/rpmfusion/vcmi.git</pre>
 

docs/developers/Building_Windows.md

@@ -1,3 +1,5 @@
+# Building VCMI for Windows
+
 # Preparations
 Windows builds can be made in more than one way and with more than one tool. This guide focuses on the simplest building process using Microsoft Visual Studio 2022
 

docs/developers/Building_iOS.md

@@ -1,3 +1,5 @@
+# Building VCMI for iOS
+
 ## Requirements
 
 1. **macOS**

docs/developers/Building_macOS.md

@@ -1,3 +1,5 @@
+# Building VCMI for macOS
+
 ## Requirements
 
 1. C++ toolchain, either of: