Remove irrelevant entries from .gitignore

https://github.com/github/gitignore/blob/main/C%2B%2B.gitignore

Our .gitignore file originated from this .gitignore template. This
template is made to be general-purpose and thus includes many things
we don't care about. We know that the SFML build won't produce files
with any of these patterns outside of the binary dir.

I alphabetized the list while I was at it.

.gitignore

@@ -1,45 +1,7 @@
-# Prerequisites
-*.d
-
-# Compiled Object files
-*.slo
-*.lo
-*.o
-*.obj
-
-# Precompiled Headers
-*.gch
-*.pch
-
-# Compiled Dynamic libraries
-*.so
-*.dylib
-*.dll
-
-# Fortran module files
-*.mod
-*.smod
-
-# Compiled Static libraries
-*.lai
-*.la
-*.a
-*.lib
-
-# Executables
-*.exe
-*.out
-*.app
-
-# Build folders
-build/
-cmake-build-*/
-
-# Cache/IDE folders
 .cache/
-.vscode/
 .idea/
 .vs/
-
+.vscode/
-# User configuration
+build/
+cmake-build-*/
 CMakeUserPresets.json