update docs for fileName, word, wordRe

src/OpenFOAM/primitives/strings/fileName/fileName.H

@@ -28,6 +28,7 @@ Class
 Description
     A class for handling file names.
 
+    A fileName is a string of characters without whitespace or quotes.
     A fileName can be
       - constructed from a char*, a string or a word
       - concatenated by adding a '/' separator

src/OpenFOAM/primitives/strings/word/word.H

@@ -28,9 +28,8 @@ Class
 Description
     A class for handling words, derived from string.
 
-    A word is a string of characters containing no whitespace and may be
-    constructed from a string by removing whitespace. Words are delimited
-    by whitespace.
+    A word is a string of characters without whitespace, quotes, slashes,
+    semicolons or brace brackets. Words are delimited by whitespace.
 
 SourceFiles
     word.C

src/OpenFOAM/primitives/strings/wordRe/wordRe.H

@@ -29,7 +29,7 @@ Description
     A wordRe is a word, but can also have a regular expression for matching
     words.
 
-    By default the constructors will generally preserve the argument as
+    By default the constructors will generally preserve the argument as a
     string literal and the assignment operators will use the wordRe::DETECT
     compOption to scan the string for regular expression meta characters
     and/or invalid word characters and react accordingly.