Remove ../include/rz_util from rz_util_includes

[kazarmy]

Your checklist for this pull request

• I've read the guidelines for contributing to this repository
• I made sure to follow the project's coding style
• I've documented or updated the documentation of every function and struct this PR changes. If not so I've explained why.
• I've added tests that prove my fix is effective or that my feature works (if possible)
• I've updated the rizin book with the relevant information (if needed)

Detailed description

This pr removes the temporary ../include/rz_util from rz_util_includes since it is rather awkward to have both an include path to include/ and to a subdir of include/.

Test plan

All non-capstone-v6-related builds are green.

Closing issues

...

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The search-and-replace was done using:

REGEX='^#.*include.*[<"]\(\(set\|ht_.*\)\.h\)[>"]' bash -c 'git grep -l "$REGEX" | xargs -n 1 sed -i "s@$REGEX@#include <rz_util/\1>@"'