Updated tokenizer to better matching when search for code snippets (#32261)

This PR improves the accuracy of Gitea's code search. 

Currently, Gitea does not consider statements such as
`onsole.log("hello")` as hits when the user searches for `log`. The
culprit is how both ES and Bleve are tokenizing the file contents (in
both cases, `console.log` is a whole token).

In ES' case, we changed the tokenizer to
[simple_pattern_split](https://www.elastic.co/guide/en/elasticsearch/reference/current/analysis-simplepatternsplit-tokenizer.html#:~:text=The%20simple_pattern_split%20tokenizer%20uses%20a,the%20tokenization%20is%20generally%20faster.).
In such a case, tokens are words formed by digits and letters. In
Bleve's case, it employs a
[letter](https://blevesearch.com/docs/Tokenizers/) tokenizer.

Resolves #32220

---------

Signed-off-by: Bruno Sofiato <bruno.sofiato@gmail.com>

tests/gitea-repositories-meta/org42/search-by-path.git/description

@@ -4,5 +4,6 @@ This repository will be used to test code search. The snippet below shows its di
 ├── avocado.md
 ├── cucumber.md
 ├── ham.md
-└── potato
-    └── ham.md
+├── potato
+|   └── ham.md
+└── example-file.js

tests/gitea-repositories-meta/org42/search-by-path.git/info/refs

@@ -3,7 +3,7 @@
 65f1bf27bc3bf70f64657658635e66094edbcb4d	refs/heads/develop
 65f1bf27bc3bf70f64657658635e66094edbcb4d	refs/heads/feature/1
 78fb907e3a3309eae4fe8fef030874cebbf1cd5e	refs/heads/home-md-img-check
-3731fe53b763859aaf83e703ee731f6b9447ff1e	refs/heads/master
+9f894b61946fd2f7b8b9d8e370e4d62f915522f5	refs/heads/master
 62fb502a7172d4453f0322a2cc85bddffa57f07a	refs/heads/pr-to-update
 4649299398e4d39a5c09eb4f534df6f1e1eb87cc	refs/heads/sub-home-md-img-check
 3fa2f829675543ecfc16b2891aebe8bf0608a8f4	refs/notes/commits

tests/gitea-repositories-meta/org42/search-by-path.git/objects/info/packs

@@ -1,2 +1,2 @@
-P pack-393dc29256bc27cb2ec73898507df710be7a3cf5.pack
+P pack-a7bef76cf6e2b46bc816936ab69306fb10aea571.pack
 

tests/gitea-repositories-meta/org42/search-by-path.git/packed-refs

@@ -4,7 +4,7 @@
 65f1bf27bc3bf70f64657658635e66094edbcb4d refs/heads/develop
 65f1bf27bc3bf70f64657658635e66094edbcb4d refs/heads/feature/1
 78fb907e3a3309eae4fe8fef030874cebbf1cd5e refs/heads/home-md-img-check
-3731fe53b763859aaf83e703ee731f6b9447ff1e refs/heads/master
+9f894b61946fd2f7b8b9d8e370e4d62f915522f5 refs/heads/master
 62fb502a7172d4453f0322a2cc85bddffa57f07a refs/heads/pr-to-update
 4649299398e4d39a5c09eb4f534df6f1e1eb87cc refs/heads/sub-home-md-img-check
 3fa2f829675543ecfc16b2891aebe8bf0608a8f4 refs/notes/commits