Create rule S2148: Underscores should be used to make large numbers readable (#4742)

* Add rust to rule S2148

* Update RSPEC

---------

Co-authored-by: yassin-kammoun-sonarsource <yassin-kammoun-sonarsource@users.noreply.github.com>
Co-authored-by: yassin-kammoun-sonarsource <yassin.kammoun@sonarsource.com>

rules/S2148/rust/metadata.json

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+{
+  "tags": [
+    "convention",
+    "clippy"
+  ],
+  "defaultQualityProfiles": [
+    "Sonar way"
+  ]
+}

rules/S2148/rust/rule.adoc

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+== Why is this an issue?
+
+Long numbers, whether integral or floating-point, can be difficult to read and understand at a glance. This can lead to mistakes when reading, writing, or maintaining code. For example, it's easy to miscount the number of zeros in a large number or misplace a decimal point. These mistakes can introduce subtle bugs that are hard to detect and debug.
+
+To improve readability, Rust allows the use of underscores as visual separators in numeric literals. By grouping digits into more manageable chunks, numbers become easier to read and understand.
+
+This practice reduces the likelihood of errors and makes the code more maintainable.
+
+== How to fix it
+
+To fix this issue, use underscores to make numeric literals more explicit and easier to read.
+
+=== Code examples
+
+==== Noncompliant code example
+
+[source,rust,diff-id=1,diff-type=noncompliant]
+----
+let large_number = 1000000000;
+let precise_float = 1234567.890123;
+----
+
+==== Compliant solution
+
+[source,rust,diff-id=1,diff-type=compliant]
+----
+let large_number = 1_000_000_000;
+let precise_float = 1_234_567.890_123;
+----
+
+== Resources
+
+=== Documentation
+
+* Clippy Lints - https://rust-lang.github.io/rust-clippy/master/index.html#unreadable_literal