Clarify which global program files paths are used and why

This also avoids using the phrase "common global program files,"
since it is easy to misread as something like "global common
program files," which would mean the same as "global common files"
(a directory like `C:\Program Files\Common Files`, which is
unrelated to the intended meaning). The phrase "Most common global
program files" is probably clear, though.

Author: EliahKagan

gix-path/src/env/git/mod.rs

@@ -39,7 +39,7 @@ where
     let varname_current = "ProgramFiles";
 
     // 64-bit relative bin dirs. So far, this is always `mingw64` or `clangarm64`, not `urct64` or
-    // `clang64`. We check `clangarm64` before `mingw64`, because in the strage case that both are
+    // `clang64`. We check `clangarm64` before `mingw64`, because in the strange case that both are
     // available, we don't want to skip over a native ARM64 executable for an emulated x86_64 one.
     let suffixes_64 = [r"Git\clangarm64\bin", r"Git\mingw64\bin"].as_slice();
 

gix-path/src/env/git/tests.rs

@@ -181,27 +181,29 @@ mod locations {
         Some(folded_text.ends_with(&folded_pattern))
     }
 
-    /// The common global program files paths on this system, by process and system architecture.
+    /// The most common global program files paths on this system, by process and system architecture.
+    ///
+    /// This omits the 32-bit ARM program files directory, as Git for Windows is never installed there.
     #[derive(Clone, Debug)]
     struct ProgramFilesPaths {
         /// The program files directory used for whatever architecture this program was built for.
         current: PathBuf,
 
-        /// The x86 program files directory regardless of the architecture of the program.
+        /// The 32-bit x86 program files directory regardless of the architecture of the program.
         ///
         /// If Rust gains Windows targets like ARMv7 where this is unavailable, this could fail.
         x86: PathBuf,
 
         /// The 64-bit program files directory if there is one.
         ///
-        /// This is present on x64 and also ARM64 systems. On an ARM64 system, ARM64 and AMD64
-        /// programs use the same program files directory while 32-bit x86 and ARM programs use
-        /// two others. Only a 32-bit system has no 64-bit program files directory.
+        /// This is present on x64 (AMD64) and also ARM64 systems. On an ARM64 system, ARM64 and
+        /// AMD64 programs use the same program files directory while 32-bit x86 and 32-bit ARM
+        /// programs use two others. Only a 32-bit system has no 64-bit program files directory.
         maybe_64bit: Option<PathBuf>,
     }
 
     impl ProgramFilesPaths {
-        /// Get the three common kinds of global program files paths without environment variables.
+        /// Get the three most common kinds of global program files paths without environment variables.
         ///
         /// The idea here is to obtain this information, which the `alternative_locations()` unit
         /// test uses to learn the expected alternative locations, without duplicating *any* of the