Improve language requirements/alternatives documentation

docs/01-about/020_programming-languages.md

@@ -29,11 +29,13 @@ Some languages require additional installations or setup steps, as noted.
 
 * **AL**
 * **Bash**
-* **C#**
+* **C#**  
+  (by default, uses the Roslyn language server (language `csharp`);
+  set language to `csharp_omnisharp` to use OmiSharp instead)
 * **C/C++**  
-  Default: clangd. Optional alternate: ccls (experimental, opt-in). 
-  For best results, provide a `compile_commands.json` at the repository root.
-  See the [C/C++ Setup Guide](../03-special-guides/cpp_setup) for details.
+  (by default, uses the clangd language server (language `cpp`) but we also support ccls (language `cpp_ccls`);
+  for best results, provide a `compile_commands.json` at the repository root;
+  see the [C/C++ Setup Guide](../03-special-guides/cpp_setup) for details.)
 * **Clojure**
 * **Dart**
 * **Elixir**  
@@ -49,7 +51,7 @@ Some languages require additional installations or setup steps, as noted.
 * **Go**  
   (requires installation of `gopls`)
 * **Groovy**  
-  (requires local groovy-language-server.jar setup via GROOVY_LS_JAR_PATH or configuration)
+  (requires local groovy-language-server.jar setup via `GROOVY_LS_JAR_PATH` or configuration)
 * **Haskell**  
   (automatically locates HLS via ghcup, stack, or system PATH; supports Stack and Cabal projects)
 * **Java**  
@@ -59,20 +61,21 @@ Some languages require additional installations or setup steps, as noted.
   (uses the pre-alpha [official kotlin LS](https://github.com/Kotlin/kotlin-lsp), some issues may appear)
 * **Lua**
 * **Markdown**  
-  (must be explicitly specified via `--language markdown` when generating project config, primarily useful for documentation-heavy projects)
+  (must explicitly enable language `markdown`, primarily useful for documentation-heavy projects)
 * **Nix**  
   (requires nixd installation)
-* **Pascal**
-  (Free Pascal/Lazarus; automatically downloads pasls binary; set PP and FPCDIR environment variables for source navigation)
-* **Perl**
+* **Pascal**  
+  (uses Pascal/Lazarus, which is automatically downloaded; set `PP` and `FPCDIR` environment variables for source navigation)
+* **Perl**  
   (requires installation of Perl::LanguageServer)
-* **PHP**
-  (by default, uses Intelephense LSP; set `INTELEPHENSE_LICENSE_KEY` environment variable for premium features; specify `php_phpactor` as your language to use the open-source [Phpactor](https://github.com/phpactor/phpactor) implementation, requires PHP 8.1+)
+* **PHP**  
+  (by default, uses the Intelephense language server (language `php`), set `INTELEPHENSE_LICENSE_KEY` environment variable for premium features;
+  we also support [Phpactor](https://github.com/phpactor/phpactor) (language `php_phpactor`), which requires PHP 8.1+)
 * **Python**
 * **R**  
   (requires installation of the `languageserver` R package)
 * **Ruby**  
-  (by default, uses [ruby-lsp](https://github.com/Shopify/ruby-lsp), specify ruby_solargraph as your language to use the previous solargraph based implementation)
+  (by default, uses [ruby-lsp](https://github.com/Shopify/ruby-lsp) (language `ruby`); use language `ruby_solargraph` to use Solargraph instead.)
 * **Rust**  
   (requires [rustup](https://rustup.rs/) - uses rust-analyzer from your toolchain)
 * **Scala**