Create rule S7428 Case mismatches in pattern arms of match expressions should be avoided (#4769)

* Create rule S7428

* Update rule.adoc

* Update metadata.json

* Update metadata.json

* 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/S7428/metadata.json

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+{
+}

rules/S7428/rust/metadata.json

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+{
+  "title": "Case mismatches in pattern arms of match expressions should be avoided",
+  "type": "BUG",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "clippy"
+  ],
+  "defaultSeverity": "Blocker",
+  "ruleSpecification": "RSPEC-7428",
+  "sqKey": "S7428",
+  "scope": "All",
+  "defaultQualityProfiles": ["Sonar way"],
+  "quickfix": "unknown",
+  "code": {
+    "impacts": {
+      "RELIABILITY": "HIGH"
+    },
+    "attribute": "LOGICAL"
+  }
+}

rules/S7428/rust/rule.adoc

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+
+== Why is this an issue?
+Case mismatches in pattern arms make some arms unreachable, likely leading to logic errors that can be difficult to debug.
+
+
+=== Code examples
+
+==== Noncompliant code example
+[source,rust,diff-id=1,diff-type=noncompliant]
+----
+match &*text.to_ascii_lowercase() {
+    "foo" => {},
+    "Bar" => {}, // Noncompliant: This arm is unreachable.
+    _ => {},
+}
+----
+
+==== Compliant solution
+
+[source,rust,diff-id=1,diff-type=compliant]
+----
+match &*text.to_ascii_lowercase() {
+    "foo" => {},
+    "bar" => {},
+    _ => {},
+}
+----
+
+== Resources
+=== Documentation
+
+* Clippy Lints - https://rust-lang.github.io/rust-clippy/master/index.html#match_str_case_mismatch