[clang] [NFC][analyzer][docs] Remove some orphaned images (PR #122249)

[Donát Nagy via cfe-commits]

NagyDonat wrote:

I assumed the correctness of the old commits, but now that I looked into it, it seems that the three `example_*.png` images were orphaned by PR https://github.com/llvm/llvm-project/pull/112831 which converted the FAQ from HTML to RST. @gamesh411 Why didn't you add these images in the RST version of the FAQ? (I know that they are old and ugly, but it seems that they have provided some additional information/context which is now missing from the FAQ.)

https://github.com/llvm/llvm-project/pull/122249