Create rule S7450 Synchronization locks should not be dropped immediately after acquisition (#4794)

* Create rule S7450

* Update metadata.json

* Update rule.adoc

* Update rule.adoc

* Update metadata.json

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Co-authored-by: sallaigy <sallaigy@users.noreply.github.com>
Co-authored-by: Gyula Sallai <gyula.sallai@sonarsource.com>

rules/S7450/metadata.json

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+{
+}

rules/S7450/rust/metadata.json

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+{
+  "title": "Synchronization locks should not be dropped immediately after acquisition",
+  "type": "BUG",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "clippy"
+  ],
+  "defaultSeverity": "Major",
+  "ruleSpecification": "RSPEC-7450",
+  "sqKey": "S7450",
+  "scope": "All",
+  "defaultQualityProfiles": ["Sonar way"],
+  "quickfix": "unknown",
+  "code": {
+    "impacts": {
+      "RELIABILITY": "HIGH"
+    },
+    "attribute": "LOGICAL"
+  }
+}

rules/S7450/rust/rule.adoc

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+
+== Why is this an issue?
+Immediately dropping a synchronization lock (e.g., `mutex`, `rwlock`) after acquiring it using `let _ = sync_lock` is often unintentional and can lead to subtle bugs. By extending the lock lifetime to the end of the scope using a named variable, the code becomes safer and intentions are clearer. If immediate drop is intended, using `std::mem::drop` conveys the intention more clearly and reduces error-prone behavior.
+
+
+=== Code examples
+
+==== Noncompliant code example
+[source,rust,diff-id=1,diff-type=noncompliant]
+----
+let _ = Mutex::new(1).lock(); // Noncompliant: Immediately drops the lock.
+----
+
+==== Compliant solution
+
+[source,rust,diff-id=1,diff-type=compliant]
+----
+// Extend lock lifetime to end of scope
+let _lock = Mutex::new(1).lock(); // Compliant: Lock remains till scope ends.
+----
+
+You can also explicitly drop the lock to convey intention:
+
+[source,rust,diff-id=1,diff-type=compliant]
+----
+std::mem::drop(Mutex::new(1).lock()); // Compliant: Clearly drops the lock.
+----
+
+== Resources
+=== Documentation
+
+* Clippy Lints - https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_lock