[NFC] fix trivial typos in documents

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@364278 91177308-0d34-0410-b5e6-96231b3b80d8

docs/CommandLine.rst

@@ -1294,7 +1294,7 @@ it cannot be guaranteed that all options will have been initialised. Hence it
 should be called from ``main``.
 
 This function can be used to gain access to options declared in libraries that
-the tool writter may not have direct access to.
+the tool writer may not have direct access to.
 
 The function retrieves a :ref:`StringMap <dss_stringmap>` that maps the option
 string (e.g. ``-help``) to an ``Option*``.

docs/LangRef.rst

@@ -421,7 +421,7 @@ added in the future:
 
     This calling convention aims to minimize overhead in the caller by
     preserving as many registers as possible (all the registers that are
-    perserved on the fast path, composed of the entry and exit blocks).
+    preserved on the fast path, composed of the entry and exit blocks).
 
     This calling convention behaves identical to the `C` calling convention on
     how arguments and return values are passed, but it uses a different set of