Fix some typos in the release notes snippets

docs/markdown/snippets/lto_threads.md

@@ -1,7 +1,7 @@
 ## Knob to control LTO thread
 
-Both the gnu linker and lld support using threads for speading up LTO, meson
+Both the gnu linker and lld support using threads for speeding up LTO, meson
 now provides a knob for this: `-Db_lto_threads`. Currently this is only
 supported for clang and gcc. Any positive integer is supported, `0` means
-`auto`. If the compiler or linker implemnets it's on `auto` we use that,
+`auto`. If the compiler or linker implements it's on `auto` we use that,
 otherwise the number of threads on the machine is used.

docs/markdown/snippets/meson_test_depends.md

@@ -12,5 +12,5 @@ using commands like the following:
 This would find the broken commit automatically while at each step
 rebuilding only those pieces of code needed to run the test.
 
-However, this change could cause failures when upgrading to 0.57, ifthe
+However, this change could cause failures when upgrading to 0.57, if the
 dependencies are not specified correctly in `meson.build`.

docs/markdown/snippets/unstable-rust-module.md

@@ -1,4 +1,4 @@
-## Untable Rust module
+## Unstable Rust module
 
 A new unstable module has been added to make using Rust with Meson easier.
 Currently it adds a single function to ease defining Rust tests.