Convert a few remaining C-style casts (for char) too static_cast

(cherry-picked from commit ce85c17)

src/build_info.cpp

@@ -76,7 +76,7 @@ std::string format_version(const SDL_version& v)
 std::string format_openssl_patch_level(uint8_t p)
 {
 	return p <= 26
-		? std::string(1, 'a' + char(p) - 1)
+		? std::string(1, 'a' + static_cast<char>(p) - 1)
 		: "patch" + std::to_string(p);
 }
 

src/config.cpp

@@ -1247,22 +1247,22 @@ std::ostream& operator<<(std::ostream& outstream, const config& cfg)
 		}
 
 		for(int j = 0; j < i - 1; j++) {
-			outstream << char(9);
+			outstream << static_cast<char>(9);
 		}
 
 		outstream << val.first << " = " << val.second << '\n';
 	}
 
 	for(const config::any_child& child : cfg.all_children_range()) {
 		for(int j = 0; j < i - 1; ++j) {
-			outstream << char(9);
+			outstream << static_cast<char>(9);
 		}
 
 		outstream << "[" << child.key << "]\n";
 		outstream << child.cfg;
 
 		for(int j = 0; j < i - 1; ++j) {
-			outstream << char(9);
+			outstream << static_cast<char>(9);
 		}
 
 		outstream << "[/" << child.key << "]\n";

src/tstring.cpp

@@ -275,8 +275,8 @@ t_string_base::t_string_base(const std::string& string, const std::string& textd
 		id = idi->second;
 	}
 
-	value_ += char(id & 0xff);
-	value_ += char(id >> 8);
+	value_ += static_cast<char>(id & 0xff);
+	value_ += static_cast<char>(id >> 8);
 	value_ += string;
 }
 
@@ -304,8 +304,8 @@ t_string_base::t_string_base(const std::string& sing, const std::string& pl, int
 		id = idi->second;
 	}
 
-	value_ += char(id & 0xff);
-	value_ += char(id >> 8);
+	value_ += static_cast<char>(id & 0xff);
+	value_ += static_cast<char>(id >> 8);
 	value_ += sing;
 	value_ += PLURAL_PART;