Fix Wasm capitalization in code comments (#1391)

According to the WebAssembly spec, Wasm is a contraction of “WebAssembly”, not an acronym, hence not using all-caps: https://webassembly.github.io/spec/core/intro/introduction.html#wasm

Author: MaxDesiatov

Sources/SwiftDriver/Jobs/AutolinkExtractJob.swift

@@ -12,7 +12,7 @@
 
 import struct TSCBasic.RelativePath
 
-// On ELF/WASM platforms there's no built in autolinking mechanism, so we
+// On ELF/Wasm platforms there's no built in autolinking mechanism, so we
 // pull the info we need from the .o files directly and pass them as an
 // argument input file to the linker.
 // FIXME: Also handle Cygwin and MinGW

Sources/SwiftDriver/Toolchains/WebAssemblyToolchain.swift

@@ -1,4 +1,4 @@
-//===-------- WebAssemblyToolchain.swift - Swift WASM Toolchain -----------===//
+//===-------- WebAssemblyToolchain.swift - Swift Wasm Toolchain -----------===//
 //
 // This source file is part of the Swift.org open source project
 //