search: allow @ and + characters

[daeho-ro]

Allow @ and + characters for search string.

brew search @11
==> Formulae
ant@1.10           go@1.17            llvm@11            mariadb@11.5
cairomm@1.14       go@1.18            mariadb@11.0       openjdk@11
cairomm@1.18       go@1.19            mariadb@11.1       openssl@1.1
clang-format@11    hdf5@1.10          mariadb@11.2       postgresql@11
gcc@11             hdf5@1.14          mariadb@11.4       spidermonkey@115

==> Casks
115                       ableton-live-suite@11     semeru-jdk-open@11
ableton-live-intro@11     corretto@11               temurin@11
ableton-live-lite@11      microsoft-openjdk@11      zulu@11
ableton-live-standard@11  paragon-extfs@11

brew search +
==> Formulae
bonnie++                  libsigc++                 mysql-connector-c++
crf++                     libsigc++@2               pcre++
crypto++                  libxml++                  png++
dvd+rw-tools              libxml++@3                quantum++
gtk+                      libxml++@4                vera++
gtk+3                     libxml++@5                voro++
kimwitu++                 mysql++

==> Casks
4k-video-downloader+      font-rounded-m+           qlc+
easy-move+resize          iina+                     starnet++
font-m+                   intel-psxe-ce-c++         tla+-toolbox
font-m+-nerd-font         logi-options+             xournal++
Warning: Did you mean to perform a regular expression search?
Surround your query with /slashes/ to search locally by regex.

If it is intended to exclude those characters, please ignore this.
I know the only allowing [a-z\d] characters will simplify the search complexity, still cool.

---

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• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew typecheck with your changes locally?
• Have you successfully run brew tests with your changes locally?

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[carlocab]

Thanks; makes sense to me!

[MikeMcQuaid]

Thanks so much for your first contribution! Without people like you submitting PRs we couldn't run this project. You rock, @daeho-ro!

[daeho-ro]

@MikeMcQuaid Actually, it is my second :)