Meta+Docs+CI: Require clang-format >= 11

Documentation/BuildInstructions.md

@@ -32,7 +32,7 @@ apt-get install curl cmake libmpc-devel gmp-devel e2fsprogs libmpfr-devel patch
 
 Ensure your gcc version is >= 10 with `gcc --version`. Otherwise, install it.
 
-On Ubuntu it's in the repositories of 20.04 (Focal) - add the `ubuntu-toolchain-r/test` PPA if you're running an older version:
+On Ubuntu it's in the repositories of 20.04 (Focal) and later - add the `ubuntu-toolchain-r/test` PPA if you're running an older version:
 ```bash
 sudo add-apt-repository ppa:ubuntu-toolchain-r/test
 ```

Documentation/CodingStyle.md

@@ -2,7 +2,7 @@
 
 For low-level styling (spaces, parentheses, brace placement, etc), all code should follow the format specified in `.clang-format` in the project root.
 
-**Important: Make sure you use `clang-format` version 10 or later!**
+**Important: Make sure you use `clang-format` version 11 or later!**
 
 This document describes the coding style used for C++ code in the Serenity Operating System project. All new code should conform to this style.
 

Documentation/UsingQtCreator.md

@@ -21,7 +21,7 @@ Qt Creator should be set up correctly now, go ahead and explore the project and
 
 ## Auto-Formatting
 
-You can use `clang-format` to help you with the [style guide](https://github.com/SerenityOS/serenity/blob/master/Documentation/CodingStyle.md). Before you proceed, check that you're actually using clang-format version 10, as some OSes still ship clang-format version 9 by default.
+You can use `clang-format` to help you with the [style guide](https://github.com/SerenityOS/serenity/blob/master/Documentation/CodingStyle.md). Before you proceed, check that you're actually using clang-format version 11, as some OSes still ship clang-format version 9 or 10 by default.
 
 - In QtCreator, go to "Help > About Plugins…"
 - Find the `Beautifier (experimental)` row (for example, by typing `beau` into the search)