Update cheatsheets

tldr/linux/lsmem

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+---
+syntax: markdown
+tags: [tldr, linux]
+source: https://github.com/tldr-pages/tldr.git
+---
+# lsmem
+
+> List the characteristics of the system's memory, including size and type of memory modules.
+> More information: <https://manned.org/lsmem>.
+
+- List memory information:
+
+`lsmem`
+
+- List memory information in JSON format:
+
+`lsmem {{[-J|--json]}}`
+
+- List memory information with size in bytes:
+
+`lsmem {{[-b|--bytes]}}`